Lithium ion sieve precursor, preparation method thereof, lithium ion sieve, preparation method and application thereof

Abstract

The application provides a lithium ion sieve precursor and a preparation method thereof, a lithium ion sieve and a preparation method and application thereof, and belongs to the field of lithium extraction from brine, and overcomes the defect that the lithium ion sieve in the prior art is not suitable for direct lithium extraction from chloride type salt lake raw brine. The preparation method of the lithium ion sieve precursor comprises the following steps: step 1, mixing a manganese-containing compound and a magnesium salt, crushing, primary sintering, and obtaining a powder; and step 2, mixing the powder obtained in step 1 and a lithium-containing compound, treating under hydrothermal conditions, and then secondary sintering, and the lithium ion sieve prepared by the method has a manganese dissolution loss of less than 3 parts per million, a cycle life of more than 2000 times, is a lithium ion sieve material with engineering application capability, and has increased adsorption selectivity to lithium ions, improved adsorption rate of lithium, reduced magnesium ion content in desorption liquid, and reduced difficulty of subsequent concentration and impurity removal.

Description

Technical Field

[0001] This invention belongs to the field of lithium extraction from brine, specifically relating to a lithium ion sieve precursor and its preparation method, a lithium ion sieve and its preparation method, and its application. Background Technology

[0002] Lithium is an indispensable raw material for supporting the development of the new energy vehicle industry. It is estimated that by 2025, the global demand for lithium will reach 1.3 million tons (equivalent to lithium carbonate), with China's demand alone reaching 782,000 tons.

[0003] Currently, China's proven lithium reserves are 16.467 million tons, of which more than 70% are from salt lakes. However, mining technology needs improvement; in 2020, salt lake lithium production was only 35,900 tons, with a cost of approximately 70,000-80,000 yuan per ton. There is an urgent need for a low-cost, environmentally friendly, efficient, and rapidly expandable salt lake lithium extraction technology to quickly increase my country's lithium salt production.

[0004] The Chaka Salt Lake, Niulangzhinu Lake, and Potassium Lake in Qinghai Province, my country, are all chloride-type salt lakes. Chloride-type salt lakes are characterized by low lithium-ion concentrations (20-50 ppm) and high magnesium-ion concentrations (50,000-100,000 ppm). Due to the small radius of magnesium hydrated ions, they easily penetrate into the effective sites of lithium-ion sieves at high concentrations, leading to a decrease in lithium adsorption efficiency. This also results in excessively high magnesium concentrations in the desorption solution, increasing the difficulty of subsequent concentration and impurity removal. Given the above-mentioned performance of conventional lithium-ion sieves in the direct extraction of lithium from chloride-type salt lake brine, it is very important to develop a lithium-ion sieve suitable for lithium extraction from chloride-type salt lake brine. Summary of the Invention

[0005] Therefore, the technical problem to be solved by this invention is to overcome the defect that lithium-ion sieves in the prior art are not suitable for direct lithium extraction from chloride-type brine, thereby providing a lithium-ion sieve precursor and its preparation method, a lithium-ion sieve and its preparation method, and its application. The lithium-ion sieve exhibits high selectivity for lithium adsorption while also reducing the magnesium ion content in the desorption solution, thus lowering the difficulty of subsequent concentration and impurity removal.

[0006] To this end, the present invention provides the following technical solution.

[0007] A method for preparing a lithium-ion sieve precursor includes the following steps:

[0008] Step 1: Mix the manganese-containing compound with magnesium salt, pulverize, and sinter in one step to obtain powder;

[0009] Step 2: Mix the powder obtained in Step 1 with a lithium-containing compound, treat it under hydrothermal conditions, and then sinter it a second time to obtain the final product.

[0010] Furthermore, the mass ratio of the magnesium salt to the manganese-containing compound is (5-30):100;

[0011] Furthermore, the temperature for the first sintering is 700-900℃, and the time is 1-72h;

[0012] The mixture of the magnesium salt and the manganese-containing compound is further ball-milled until the particle size reaches the micrometer level.

[0013] Furthermore, the magnesium salt includes at least one of magnesium chloride, magnesium sulfate, and magnesium carbonate;

[0014] Further, the manganese-containing compound includes one or more of manganese carbonate, manganese hydroxide, manganese oxide, or manganese sulfate;

[0015] The lithium-containing compound further includes one or more of lithium hydroxide, lithium carbonate, lithium chloride, or lithium fluoride.

[0016] Furthermore, step 2 possesses at least one of the following features:

[0017] A. The mass ratio of the powder to the lithium-containing compound is (7-10):5;

[0018] B. The hydrothermal conditions include a pressure of 0.1–0.6 MPa, a temperature of 110–180 °C, and a reaction time of 12–72 h;

[0019] C. The secondary sintering temperature is 350-500℃, and the time is 0.5-72h.

[0020] A lithium-ion sieve precursor is prepared by the method described above.

[0021] A lithium-ion sieve, wherein the raw materials for the lithium-ion sieve, by weight percentage, comprise:

[0022] The lithium-ion sieve precursor of claim 5 comprises 5-40%;

[0023] 5-10% adhesive;

[0024] Surfactant 0.3-3%;

[0025] The remainder is solvent.

[0026] Furthermore, the raw materials for the lithium-ion sieve, by weight percentage, include:

[0027] The lithium-ion sieve precursor of claim 5 comprises 20-30%;

[0028] Adhesive 7-9%;

[0029] Surfactant 1-2%;

[0030] The remainder is solvent.

[0031] A lithium-ion sieve, wherein the binder is one or more selected from polyvinyl chloride, polyvinylidene fluoride, and polytetrafluoroethylene;

[0032] Furthermore, the surfactant is one or more of the following: sodium linear alkylbenzene sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, ammonium fatty alcohol polyoxyethylene ether sulfate, sodium lauryl sulfate, and lauroyl glutamic acid;

[0033] Furthermore, the solvent is one or more of N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide.

[0034] A method for preparing a lithium-ion sieve includes the following steps:

[0035] The lithium-ion sieve precursor, the binder, the surfactant, and the solvent are uniformly mixed to prepare a slurry; the slurry is then granulated in water to obtain a lithium-ion sieve.

[0036] Optionally, in the mixing step, the stirring speed is 500-8000 rpm, the temperature is 30-80℃, and the time is 1-6 hours;

[0037] Optionally, the slurry is transferred to a container with holes at the bottom, and gas is introduced above the slurry to pressurize it, causing the slurry to fall into water and form granules;

[0038] Optionally, the aperture of the hole is 0.05 to 2 mm, and the pressure of the gas is 0.05 to 1 MPa.

[0039] Application of lithium ion sieves or lithium ion sieves prepared by root preparation methods in lithium extraction from brine.

[0040] The technical solution of this invention has the following advantages:

[0041] 1. The method for preparing lithium-ion sieve precursor provided by the present invention includes the following steps: Step 1, mixing a manganese-containing compound with a magnesium salt, pulverizing, and sintering once to obtain powder; Step 2, mixing the powder obtained in Step 1 with a lithium-containing compound, treating under hydrothermal conditions, and then sintering a second time to obtain the final product.

[0042] Magnesium doping increases the proportion of tetravalent manganese ions in the lithium-ion sieve precursor, improving the stability of the lithium-ion sieve and effectively preventing manganese dissolution. The resulting lithium-ion sieve exhibits extremely high stability, with a manganese dissolution rate reduced to below 0.03% and a cycle life exceeding 2000 cycles, making it a lithium-ion sieve material with engineering application potential.

[0043] Meanwhile, magnesium doping also increases the concentration of magnesium ions in the solid phase of the lithium ion sieve, reduces the magnesium ion concentration gradient during adsorption of chloride-type salt lake brine, thereby increasing the adsorption selectivity for lithium ions and improving the adsorption rate of lithium. At the same time, it also reduces the magnesium ion content in the desorption liquid, reducing the difficulty of subsequent concentration and impurity removal.

[0044] 2. The lithium-ion sieve provided by the present invention comprises 5-40% lithium-ion sieve precursor; 5-10% binder; 0.3-3% surfactant; and the balance being solvent.

[0045] In addition to the aforementioned advantages, the lithium-ion sieve of the present invention also has the following advantages: on the one hand, the presence of a surfactant inhibits the hydration energy, which is much greater than that of Li. + Mg (-510.4 kJ / mol) 2+ The (-1862 kJ / mol) dehydration enters the effective ion adsorption sites, improving the adsorption efficiency of lithium. Simultaneously, it accelerates the diffusion of brine within the lithium ion sieve, increasing the lithium recovery rate at high flow rates. Furthermore, the presence of surfactants enhances the cleaning effect of water washing on impurity ions at non-effective sites, preventing magnesium ions from being entrained in the desorption solution.

[0046] 3. The method for preparing lithium-ion sieves provided by the present invention involves feeding the slurry formed after mixing raw materials into deionized water for granulation, thereby obtaining a shaped lithium-ion sieve adsorbent. Detailed Implementation

[0047] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0048] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0049] Example 1

[0050] This embodiment provides a method for preparing a lithium-ion sieve, including the following steps:

[0051] (1) Preparation of lithium-ion precursors:

[0052] Step 1: Mix 10g of manganese carbonate and 1.5g of magnesium carbonate, and then ball mill them to the micron level.

[0053] Step 2: Sinter at 800℃ for 48 hours in air atmosphere.

[0054] Step 3: Mix 9g of sintered powder with 5g of lithium hydroxide monohydrate, and perform a hydrothermal reaction at 0.4MPa and 150℃ for 48h.

[0055] Step 4: Sinter the powder obtained in step 3 at 450°C for 48 hours in air atmosphere to obtain lithium ion sieve precursor.

[0056] (2) Mix 10g of lithium ion sieve precursor, 4g of polyvinylidene fluoride (Solvay PVDF 5130 powder), 0.75g of sodium dodecylbenzenesulfonate and 30g of N-methylpyrrolidone obtained in step (1), and stir at 4000rpm for 4h at 60℃ to obtain a slurry.

[0057] (3) Granulation: The slurry is transferred to a container with holes at the bottom. The holes are 1 mm in diameter. The slurry is pressurized by air at 0.8 MPa above it. The slurry falls into the water pool below under the action of gravity and pressure, thus obtaining the shaped granules.

[0058] Example 2

[0059] This embodiment provides a method for preparing a lithium-ion sieve, including the following steps:

[0060] (1) Preparation of lithium-ion sieve precursor:

[0061] Step 1: Mix 10g of manganese carbonate and 0.5g of magnesium carbonate, and then ball mill them to the micron level.

[0062] Step 2: Sinter at 700℃ for 1 hour in air atmosphere.

[0063] Step 3: Mix 7g of sintered powder with 5g of lithium hydroxide monohydrate, and perform a hydrothermal reaction at 0.1MPa and 110℃ for 12h.

[0064] Step 4: Sinter the powder obtained in step 3 at 350°C for 1 hour in air atmosphere to obtain lithium ion sieve precursor.

[0065] (2) Mix 10g of lithium ion sieve precursor, 2.5g of polyvinylidene fluoride (Solvay PVDF 5130 powder), 0.75g of sodium dodecylbenzenesulfonate and 15g of N-methylpyrrolidone obtained in step (1), and stir at 500rpm for 1h at 30℃ to obtain a slurry.

[0066] (3) Granulation: The slurry is transferred to a container with holes at the bottom. The holes are 0.05 mm in diameter. Air pressure of 0.05 MPa is applied above the slurry. The slurry falls into the water pool below under the action of gravity and pressure, thus obtaining the shaped granules.

[0067] Example 3

[0068] This embodiment provides a method for preparing a lithium-ion sieve, including the following steps:

[0069] (1) Preparation of lithium-ion sieve precursor:

[0070] Step 1: Mix 10g of manganese carbonate and 3g of magnesium carbonate, then ball mill to the micron level.

[0071] Step 2: Sinter at 900℃ for 72 hours in air atmosphere.

[0072] Step 3: Mix 10g of the sintered powder with 5g of lithium hydroxide monohydrate, and perform a hydrothermal reaction at 0.6MPa and 180℃ for 72h.

[0073] Step 4: Sinter the powder obtained in step 3 at 500°C for 72 hours in air atmosphere to obtain lithium ion sieve precursor.

[0074] (2) Mix 10g of lithium ion sieve precursor, 10g of polyvinylidene fluoride (Solvay PVDF 5130 powder), 0.6g of sodium dodecylbenzenesulfonate and 80g of N-methylpyrrolidone obtained in step (1), and stir at 8000rpm for 6h at 80℃ to obtain a slurry.

[0075] (3) Granulation: The slurry is transferred to a container with holes at the bottom. The holes are 2 mm in diameter. Air pressure of 1 MPa is applied above the slurry. The slurry falls into the water pool below under the action of gravity and pressure, thus obtaining the shaped granules.

[0076] Example 4

[0077] This embodiment provides a method for preparing a lithium-ion sieve, including the following steps:

[0078] (1) Preparation of lithium-ion sieve precursor:

[0079] Step 1: Mix 10g of manganese carbonate and 2.5g of magnesium sulfate, and then ball mill them to the micron level.

[0080] Step 2: Sinter at 750℃ for 24 hours in air atmosphere.

[0081] Step 3: Mix 7g of sintered powder with 5g of lithium hydroxide monohydrate, and perform a hydrothermal reaction at 0.2MPa and 130℃ for 24h.

[0082] Step 4: Sinter the powder obtained in step 3 at 400°C for 24 hours in air atmosphere to obtain lithium ion sieve precursor.

[0083] (2) Mix 10g of lithium ion sieve precursor, 2.8g of polyvinylidene fluoride (Solvay PVDF 5130 powder), 0.6g of sodium lauryl sulfate and 20g of N,N-dimethylformamide obtained in step (1), and stir at 3000rpm for 3h at 80℃ to obtain a slurry.

[0084] (3) Granulation: The slurry is transferred to a container with holes at the bottom. The holes are 0.08 mm in diameter. Air pressure of 0.08 MPa is applied above the slurry. The slurry falls into the water pool below under the action of gravity and pressure, thus obtaining the shaped granules.

[0085] Example 5

[0086] This embodiment provides a method for preparing a lithium-ion sieve, including the following steps:

[0087] (1) Preparation of lithium-ion sieve precursor:

[0088] Step 1: Mix 10g of manganese carbonate and 2g of magnesium sulfate, then ball mill to the micron level.

[0089] Step 2: Sinter at 850℃ for 60 hours in air atmosphere.

[0090] Step 3: Mix 9g of sintered powder with 5g of lithium hydroxide monohydrate, and perform a hydrothermal reaction at 0.5MPa and 160℃ for 60h.

[0091] Step 4: Sinter the powder obtained in step 3 at 450°C for 60 hours in air atmosphere to obtain lithium ion sieve precursor.

[0092] (2) Mix 10g of lithium ion sieve precursor, 5g of polyvinylidene fluoride (Solvay PVDF 5130 powder), 2g of sodium lauryl sulfate and 50g of N,N-dimethylformamide obtained in step (1), and stir at 6000rpm for 5h at 70℃ to obtain a slurry.

[0093] (3) Granulation: The slurry is transferred to a container with holes at the bottom. The holes are 1.5 mm in diameter. The slurry is pressurized by air at 0.08 MPa above it. The slurry falls into the water pool below under the action of gravity and pressure, thus obtaining the shaped granules.

[0094] Comparative Example 1

[0095] The preparation method of this comparative lithium-ion sieve is as follows:

[0096] (1) A mixed solution was prepared using MnCl2·4H2O and MgCl2·6H2O as raw materials. LiOH·H2O was added to adjust the pH of the mother liquor to be greater than 11.0, and the solution was stirred. H2O2 was added dropwise to obtain a brownish-black suspension. The precipitate was filtered, washed with deionized water, and the filter cake was dried. The dried sample was calcined at 450℃ for 4 hours, cooled, and then ground to obtain the lithium ion sieve precursor LiMg. 0.56 Mn 1.50 O4.

[0097] (2) Mix 10g of lithium ion sieve precursor, 4g of polyvinylidene fluoride (Solvay PVDF 5130 powder), 0.75g of sodium dodecylbenzenesulfonate and 30g of N-methylpyrrolidone obtained in step (1), and stir at 4000rpm for 4h at 60℃ to obtain a slurry.

[0098] (3) Granulation: The slurry is transferred to a container with holes at the bottom. The holes are 1 mm in diameter. The slurry is pressurized by air at 0.8 MPa above it. The slurry falls into the water pool below under the action of gravity and pressure, thus obtaining the shaped granules.

[0099] Comparative Example 2

[0100] Except for the following, the rest of the content is the same as in Example 1.

[0101] No surfactant was added in step (2).

[0102] Experimental Example 1

[0103] Lithium extraction experiments were conducted on the raw brine of Chaka Salt Lake using lithium-ion sieves prepared in the examples and comparative examples: The lithium-ion sieves prepared in the examples and comparative examples were acidified: The lithium-ion sieves were added to hydrochloric acid solution, stirred, filtered, and dried. 20 mL of the acidified lithium-ion sieve was taken and adsorbed onto the raw brine of Chaka Salt Lake at 15°C and a flow rate of 30 times the space volume / hour for 10 hours.

[0104] The components of the original brine of Chaka are shown in Table 1, and the test results are shown in Table 2. The lithium recovery rate is calculated as follows: Lithium recovery rate = (1 - lithium ion concentration in the adsorbed tail liquid / lithium ion concentration in the original brine) * 100%.

[0105] Table 1. Components of the original brine in Chaka Salt Lake

[0106] Concentration (ppm) 4700 3160 93308 12891 15 82 299038

[0107] Table 2 Lithium recovery rate

[0108] Example 1 78％ Example 2 70％ Example 3 71％ Example 4 75％ Example 5 73％ Comparative Example 1 47％ Comparative Example 2 61％

[0109] As shown in Table 2, the lithium-ion sieve prepared by the present invention can significantly improve the lithium recovery rate.

[0110] Experimental Example 2

[0111] The lithium-ion sieve after the lithium extraction experiment was washed with water, and then desorption was performed. The specific desorption method was as follows: using a flow rate of 20 times the volumetric velocity, at H₂O… + The components of the desorption solution obtained after 15 minutes of desorption with 2 mol / L sulfuric acid are shown in Table 3.

[0112] Table 3 Desorption solution composition

[0113]

[0114] As shown in Table 3, the lithium ion sieve of the present invention significantly improves the selectivity for lithium ions, significantly increases the adsorption capacity, and significantly reduces other ionic components in the desorption solution.

[0115] Experimental Example 3

[0116] The manganese dissolution loss in the lithium-ion sieve was tested using atomic absorption spectrometry. The manganese concentration in the solution was determined by atomic absorption spectrometry. The manganese dissolution loss was calculated as follows: (Manganese concentration in the adsorption tail liquid * Adsorption tail liquid volume - Manganese concentration in the original brine * Original brine volume + Manganese concentration in the washing liquid * Washing liquid volume + Manganese concentration in the desorption liquid * Desorption liquid volume) / Manganese content of the adsorbent * 100%. The manganese dissolution loss is shown in Table 4. The adsorption tail liquid refers to the tail liquid generated after the original brine is adsorbed by lithium ions by the lithium-ion sieve.

[0117] Table 4 Manganese dissolution

[0118] Example 1 0.013％ Example 2 0.027％ Example 3 0.028％ Example 4 0.020％ Example 5 0.017％ Comparative Example 1 0.14％ Comparative Example 2 0.87％

[0119] As shown in Table 4, the lithium ion screen of the present invention significantly reduces the problem of manganese dissolution during the lithium ion screen cycle, enabling the material to be applied in engineering.

[0120] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A lithium-ion sieve, characterized in that, The raw materials for the lithium-ion sieve, by weight percentage, include: Lithium-ion sieve precursors: 5-40%; Adhesive 5~10%; Surfactant 0.3~3%; The remainder is solvent; The preparation method of the lithium-ion sieve precursor includes the following steps: Step 1: Mix the manganese-containing compound with magnesium salt, pulverize, and sinter in one step to obtain powder; Step 2: Mix the powder obtained in Step 1 with a lithium-containing compound, treat it under hydrothermal conditions, and then sinter it a second time to obtain the final product. In step 1, the mass ratio of the magnesium salt to the manganese-containing compound is (15-25):100; the temperature of the first sintering is 700-900℃, and the time is 1-72h; the mixture of the magnesium salt and the manganese-containing compound is ball-milled until the particle size reaches the micron level. In step 2, the temperature of the secondary sintering is 350-500℃, and the time is 0.5-72h. The surfactant is one or more of the following: sodium linear alkylbenzene sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, ammonium fatty alcohol polyoxyethylene ether sulfate, sodium lauryl sulfate, and lauroyl glutamic acid.

2. The lithium-ion sieve according to claim 1, characterized in that, It has at least one of the following characteristics: (1) The magnesium salt includes at least one of magnesium chloride, magnesium sulfate, and magnesium carbonate; (2) The manganese-containing compound includes one or more of manganese carbonate, manganese hydroxide, manganese oxide, or manganese sulfate; (3) The lithium-containing compound includes one or more of lithium hydroxide, lithium carbonate, lithium chloride or lithium fluoride.

3. The lithium-ion sieve according to any one of claims 1-2, characterized in that, Step 2 has at least one of the following characteristics: A. The mass ratio of the powder to the lithium-containing compound is (7-10):5; B. The hydrothermal conditions include a pressure of 0.1~0.6MPa, a temperature of 110~180℃, and a reaction time of 12-72h.

4. The lithium-ion sieve according to claim 1, characterized in that, The raw materials for the lithium-ion sieve, by weight percentage, include: Lithium-ion sieve precursors: 20-30%; Adhesive 7~9%; Surfactant 1~2%; The remainder is solvent.

5. The lithium-ion sieve according to claim 1 or 4, characterized in that, At least one of conditions (1)-(2) must be satisfied: (1) The adhesive is one or more of polyvinyl chloride, polyvinylidene fluoride, and polytetrafluoroethylene; (2) The solvent is one or more of N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide.

6. A method for preparing a lithium-ion sieve according to any one of claims 1-5, characterized in that, Includes the following steps: The lithium-ion sieve precursor, the binder, the surfactant, and the solvent are uniformly mixed to prepare a slurry; the slurry is then granulated in water to obtain a lithium-ion sieve.

7. The method for preparing a lithium-ion sieve according to claim 6, characterized in that, During the mixing step, the stirring speed is 500~8000 rpm, the temperature is 30-80℃, and the time is 1-6h.

8. The method for preparing a lithium-ion sieve according to claim 6, characterized in that, The slurry is transferred to a container with holes at the bottom, and gas is introduced above the slurry to pressurize it, causing the slurry to fall into the water and form granules.

9. The method for preparing a lithium-ion sieve according to claim 8, characterized in that, The aperture of the hole is 0.05~2mm, and the pressure of the gas is 0.05~1MPa.

10. The application of the lithium ion sieve according to any one of claims 1-5 or the lithium ion sieve prepared by the preparation method according to any one of claims 6-8 in lithium extraction from brine.

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