Method for extracting lithium from chloride type salt lake brine

Abstract

The application discloses a method for extracting lithium from chloride type salt lake raw brine, and belongs to the technical field of lithium extraction from brine, and overcomes the low lithium adsorption efficiency of the prior art method for extracting lithium from chloride type salt lake raw brine. The method comprises the following steps: adsorbing lithium ions in the chloride type salt lake raw brine by lithium ion sieves; stopping the input of the chloride type salt lake raw brine after the adsorption is completed, and desorbing the lithium ion sieves after water washing; a plurality of adsorption columns are arranged in parallel in a tower cavity of an adsorption tower main body; and the raw material of the lithium ion sieves comprises 5-40% of lithium ion sieve precursors, 5-10% of a bonding agent, 0.3-3% of a surfactant, and the balance of a solvent. The lithium ion sieve precursors are prepared by mixing a manganese-containing compound and a magnesium salt, primary sintering to obtain a powder, mixing the powder with a lithium-containing compound, and processing under hydrothermal conditions, and then secondary sintering. The method can improve the lithium adsorption efficiency.

Description

Technical Field

[0001] This invention belongs to the field of brine lithium extraction technology, specifically relating to a method for extracting lithium from chloride-type salt lake brine. Background Technology

[0002] 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 the effective sites of lithium-ion sieves at high concentrations, leading to reduced lithium adsorption efficiency. This also results in excessively high magnesium concentrations in the eluent, increasing the difficulty of subsequent concentration and impurity removal. These two factors mean that the performance of existing lithium-ion sieves in the direct lithium extraction from raw brine of chloride-type salt lakes needs improvement.

[0003] Current technologies commonly employ adsorption towers to extract lithium from brine. Commonly available adsorption towers include single- or two-chamber column adsorption towers and continuous ion-exchange adsorption tower groups, all developed specifically for the characteristics of traditional lithium molecular sieves. Compared to lithium molecular sieves, lithium-ion sieves offer higher adsorption-desorption efficiency and higher adsorption capacity. However, commercially available column adsorption towers and continuous ion-exchange adsorption tower groups, due to their excessively large tower chamber volumes, cannot fully utilize the characteristics of lithium-ion sieves. This often results in a situation where most of the lithium-ion sieve adsorbent is not in an effective adsorption state for most of the time, ultimately leading to low lithium extraction efficiency. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect of low lithium adsorption efficiency in the existing chloride-type brine lithium extraction method, thereby providing a chloride-type brine lithium extraction method with high lithium adsorption efficiency.

[0005] To this end, the present invention provides the following technical solution.

[0006] This invention provides a method for lithium extraction from chloride-type brine in salt lakes, comprising the following steps: A lithium-ion sieve is loaded into an adsorption tower, and chloride-type brine from the salt lake is passed into the adsorption tower. The lithium-ion sieve adsorbs lithium ions in the chloride-type brine. After adsorption is completed, the flow of chloride-type brine from the salt lake is stopped, and the lithium-ion sieve is washed with water to desorb the ions. The adsorption-desorption cycle is repeated to extract lithium. The adsorption tower includes a main body, and multiple adsorption columns are arranged in parallel inside the tower cavity of the main body; The raw materials of the lithium-ion sieve, by mass percentage, include: 5-40% lithium-ion sieve precursor, 5-10% binder, 0.3-3% surfactant, and 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.

[0007] Furthermore, it possesses 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; (4) The adhesive is one or more of polyvinyl chloride, polyvinylidene fluoride, and polytetrafluoroethylene; (5) 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; (6) The solvent is one or more of N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide.

[0008] Furthermore, in the method for preparing the lithium-ion sieve precursor, step 1 includes at least one of the following features: (1) The mass ratio of the magnesium salt to the manganese-containing compound is (5-30):100; (2) The temperature of the first sintering is 700-900℃ and the time is 1-72h; (3) The mixture of the magnesium salt and the manganese-containing compound is ball-milled until the particle size reaches the micron level.

[0009] Furthermore, in the method for preparing the lithium-ion sieve precursor, step 2 possesses at least one of the following features: 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; C. The secondary sintering temperature is 350-500℃, and the time is 0.5-72h.

[0010] Furthermore, the preparation method of the lithium-ion sieve 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. Optionally, in the mixing step, the stirring speed is 500~8000 rpm, the temperature is 30-80℃, and the time is 1-6h; 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 the water and form granules. Optionally, the aperture of the hole is 0.05~2mm, and the pressure of the gas is 0.05~1MPa.

[0011] Furthermore, each of the adsorption columns is provided with a cover with mesh on both the upper and lower end faces. The cover can restrict the overflow of lithium ions inside the adsorption column while allowing liquid to pass through. Optionally, the amount of lithium-ion sieves loaded in each adsorption column is 50-95% of the column volume; Optionally, the flow rate of the raw brine from the chloride-type salt lake into the adsorption tower is 2 to 200 times the space volume per hour (i.e., the flow rate of the raw brine into the adsorption tower is 2 to 200 times the total volume of the entire adsorption column per hour).

[0012] Furthermore, the adsorption tower also includes an ultrasonic generator; the ultrasonic generator is installed in both the top cavity and the bottom cavity of the tower cavity; Preferably, the ultrasonic generator is activated during water washing, and the frequency of the ultrasonic generator is controlled to be 10~150kHz.

[0013] Furthermore, the adsorption tower also includes a vibrating motor; the vibrating motor is located outside the main body, and the vibrating motor is connected to the outer wall of the main body through a rigid rod; Preferably, the vibrating motor is started during water washing, and the frequency of the vibrating motor is controlled to be 5~100Hz.

[0014] Furthermore, the adsorption column satisfies at least one of the following conditions: (1) The end face of each of the adsorption columns is a regular hexagonal structure, and two adjacent adsorption columns are seamlessly spliced ​​together; (2) The side length of each adsorption column ranges from 0.5cm to 5cm; (3) The height of each adsorption column ranges from 5cm to 50cm; (4) Multiple adsorption columns are provided in the tower cavity along the height direction of the main body, and multiple adsorption columns in the same layer form an adsorption combination; Preferably, the adsorption tower further includes a tray, and the top and bottom surfaces of the adsorption assembly are provided with the tray; the tray surface is provided with a plurality of mounting holes adapted to the shape of the end face of the adsorption column, and the end face of each adsorption column is inserted into the mounting hole; Preferably, the adsorption tower further includes a water distributor, which is disposed below the adsorption assembly, and the water distributor ensures that the liquid flows evenly through each adsorption column in the same adsorption assembly.

[0015] Furthermore, during the first desorption, H+ is introduced. + The first desorption solution is obtained by desorption with an acid solution of concentration of 1~2 mol / L; during the second desorption, acid is added to the first desorption solution to remove H+. + The concentration was adjusted to the initial level, and the adjusted first desorption solution was used to desorb lithium ions from the sieve to obtain the second desorption solution. For the third desorption, acid was added to the second desorption solution to remove H+. + The concentration was adjusted to the initial level, and the lithium-ion sieve was desorbed using the adjusted second desorption solution to obtain the third desorption solution.

[0016] The chloride-type brine from the salt lake is passed into an adsorption tower, and lithium ions in the chloride-type brine are adsorbed by a lithium ion sieve for 0.5 to 10 hours.

[0017] During desorption, H+ is introduced. + The lithium ion sieve was desorbed by an acid solution with a concentration of 1~2 mol / L.

[0018] The eluent obtained by this invention has a low concentration of impurity ions. Therefore, the following method can be used for desorption to increase the lithium ion concentration in the eluent and reduce the burden on subsequent concentration and impurity removal processes: During the first desorption, H+ is introduced... + The first desorption solution is obtained by desorption with an acid solution of concentration of 1~2 mol / L; during the second desorption, acid is added to the first desorption solution to remove H+. + The concentration was adjusted to the initial level, and the adjusted first desorption solution was used to desorb lithium ions from the sieve to obtain the second desorption solution. For the third desorption, acid was added to the second desorption solution to remove H+. + The concentration is adjusted to the initial level, and the lithium ion sieve is desorbed using the adjusted second desorption solution to obtain the third desorption solution; and so on, the adsorption-desorption cycle is repeated.

[0019] Furthermore, the diameter of the lithium-ion sieve adsorbent particles filling each of the adsorption columns ranges from 0.3 mm to 2 mm.

[0020] Furthermore, the main body includes an inlet and an outlet. Both the inlet and outlet of the main body are connected to flexible pipes.

[0021] Furthermore, by mass percentage, the raw materials of the lithium-ion sieve include: 20-30% lithium-ion sieve precursor; 7-9% binder; 1-2% surfactant; and the balance being solvent.

[0022] The technical solution of this invention has the following advantages: 1. The method for lithium extraction from chloride-type brine in salt lakes provided by this invention includes the following steps: loading a lithium-ion sieve into an adsorption tower, passing chloride-type brine into the adsorption tower, and adsorbing lithium ions in the chloride-type brine using the lithium-ion sieve; stopping the flow of chloride-type brine after adsorption, washing the lithium-ion sieve with water, and then desorbing; and repeating the adsorption-desorption steps to extract lithium. The adsorption tower includes a main body, and multiple adsorption columns are arranged in parallel inside the tower cavity of the main body. The raw materials of the lithium-ion sieve, by mass percentage, include: 5-40% lithium-ion sieve precursor, 5-10% binder, 0.3-3% surfactant, and the remainder is solvent. The preparation method of the lithium-ion sieve precursor 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.

[0023] The adsorption tower of this invention features multiple adsorption columns arranged in parallel within its main chamber. Compared to traditional adsorption towers, each column is smaller, allowing the lithium-ion sieves within each column to disperse freely in the liquid. This ensures that the liquid flowing through the adsorption columns makes full contact with the lithium-ion sieves without creating runoff. This avoids repeated scouring of saturated lithium-ion sieves by high-lithium-concentration brine and prolonged scouring of unadsorbed lithium-ion sieves by low-lithium-concentration brine. This significantly reduces the time of a single adsorption-desorption cycle and improves adsorption-desorption efficiency. The parallel arrangement of multiple adsorption columns in this invention is ideal for high-flow-rate adsorption. Since the lithium-ion concentration in chloride-type brine is generally low, high flow rates ensure the overall production efficiency of the lithium recovery process.

[0024] The raw material for lithium-ion sieves includes 5-40% lithium-ion sieve precursor; 5-10% binder; 0.3-3% surfactant; and the balance being solvent. On the one hand, the presence of surfactants inhibits the hydration energy, which is much greater than that of Li. + Mg (-510.4 kJ / mol) 2+ The (-1862 kJ / mol) dehydration process allows the brine to enter effective ion adsorption sites, while simultaneously accelerating the diffusion rate of the brine within the lithium ion sieve, thus improving lithium recovery 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.

[0025] The lithium-ion sieve prepared using the method of this invention has a manganese loss reduced to below 0.03% and a cycle life exceeding 2000 cycles, making it a mature lithium-ion sieve material with engineering application capabilities. The significant doping of magnesium increases the magnesium ion concentration in the solid phase of the lithium-ion sieve, reducing the magnesium ion concentration gradient during adsorption of chloride-type brine from salt lakes. This increases the adsorption selectivity for lithium ions and improves the lithium adsorption rate. Simultaneously, it reduces the magnesium ion content in the desorption solution, lowering the difficulty of subsequent concentration and impurity removal.

[0026] 2. The method for lithium extraction from chloride-type brine in salt lakes provided by this invention uses an adsorption tower that also includes an ultrasonic generator and a oscillating motor. During water washing, the ultrasonic oscillation process can better clean magnesium impurity ions remaining at non-effective sites on the lithium ion sieve, resulting in higher water washing efficiency and significant water savings.

[0027] 3. The lithium extraction method from chloride-based brine in salt lakes provided by this invention involves feeding the slurry formed after mixing raw materials into deionized water for granulation, thereby obtaining a shaped lithium-ion sieve. The lithium-ion sieve prepared by this invention exhibits extremely high stability in lithium extraction processes from chloride-based brine systems with high magnesium content, reducing manganese loss to below 0.03%, and has a cycle life exceeding 2000 cycles. It is a mature lithium-ion sieve material with engineering application capabilities. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the adsorption column in the adsorption tower in an embodiment of the present invention; Figure 2 This is a schematic diagram of the tray in the adsorption tower in an embodiment of the present invention; Figure 3 This is a schematic diagram of the adsorption tower in an embodiment of the present invention.

[0030] Reference numerals: 1. Adsorption column; 2. Cover; 3. Tray; 4. Mounting hole; 5. Main body; 6. Outlet; 7. Inlet; 8. Ultrasonic generator; 9. Vibration motor. Detailed Implementation

[0031] 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.

[0032] 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.

[0033] Figure 1 This is a schematic diagram of the adsorption column in the adsorption tower in an embodiment of the present invention; Figure 2 This is a schematic diagram of the tray in the adsorption tower in an embodiment of the present invention; Figure 3 This is a schematic diagram of the adsorption tower in an embodiment of the present invention; as shown. Figure 1 , Figure 2 as well as Figure 3 As shown, this embodiment provides an adsorption tower, comprising at least: a main body 5 having an inlet 7 and an outlet 6. For example, the outlet 6 is located at the top of the main body 5, and the inlet 7 is located at the bottom of the main body 5. Placing the inlet at the bottom ensures the distribution of the raw brine among the adsorption columns, allowing sufficient contact between the raw brine and the lithium-ion sieve. Multiple adsorption columns 1 are arranged side-by-side within the tower cavity of the main body 5. For example, multiple adsorption columns 1 are arranged side-by-side at the same height along the horizontal direction. Alternatively, multiple adsorption columns 1 can be arranged at different heights within the tower cavity. For example, each adsorption column 1 has a cover 2 with mesh openings on both its upper and lower end faces. The size of the mesh openings is selected according to the particle diameter of the lithium-ion sieve, allowing the cover 2 to restrict the overflow of lithium-ion sieve particles from the adsorption column 1 while allowing liquid to pass through.

[0034] The adsorption tower provided in this embodiment has multiple adsorption columns 1 arranged in parallel in the tower cavity of the main body 5. Compared with the original adsorption tower, the volume of each adsorption column 1 is smaller, so that the lithium ion screen in each adsorption column 1 can be freely dispersed in the liquid. This ensures that when the liquid flows through the adsorption column 1, it can fully contact the lithium ion screen without forming runoff. This avoids the lithium ion screen that has been saturated being repeatedly washed by brine with high lithium ion concentration, and the lithium ion screen that has not adsorbed lithium being washed by brine with low lithium ion concentration for a long time. This can significantly reduce the time of a single adsorption-desorption cycle and improve the adsorption-desorption efficiency.

[0035] Each adsorption column 1 has a hexagonal end face, and two adjacent adsorption columns 1 are seamlessly joined together.

[0036] The side length of each adsorption column 1 ranges from 0.5cm to 5cm; the height of each adsorption column 1 ranges from 5cm to 50cm.

[0037] Among them, multiple adsorption columns 1 are arranged in the tower cavity along the height direction of the main body 5, and multiple adsorption columns 1 in the same layer form an adsorption combination.

[0038] The adsorption tower also includes a tray 3, which is provided on both the top and bottom surfaces of the adsorption assembly. The tray 3 has several mounting holes 4 that are adapted to the shape of the end face of the adsorption column 1. The end face of each adsorption column 1 is inserted into the mounting hole 4, and the adsorption column 1 and the mounting hole 4 can be connected by threads.

[0039] The water distributor is located below the adsorption assembly and is designed to ensure that the liquid flows evenly through each adsorption column 1 within the same adsorption assembly.

[0040] The adsorption tower also includes an ultrasonic generator 8 and an oscillating motor 9; the ultrasonic generator 8 is installed in both the top cavity and the bottom cavity of the tower cavity; the oscillating motor 9 is located outside the main body 5 and is connected to the outer wall of the main body 5 through a rigid rod.

[0041] The lithium-ion sieves filled in each adsorption column 1 have a particle diameter ranging from 0.3 mm to 2 mm.

[0042] Among them, the outlet 6 and inlet 7 of the main body 5 are both connected to flexible pipes.

[0043] Specifically, such as Figure 1 As shown, its upper and lower surfaces are regular hexagons with side lengths of 0.5cm-5cm and heights of 5cm-50cm. Due to the high adsorption efficiency of lithium-ion sieves, a column height of 5cm-50cm for a single adsorption column 1 can fully utilize the adsorption efficiency of the lithium-ion sieve, avoiding repeated scouring of the saturated lithium-ion sieve by high-lithium-ion concentration brine, and also preventing the lithium-ion sieve without adsorbed lithium from being scouring by low-lithium-ion concentration brine for a long time. Simultaneously, it significantly reduces the time of a single adsorption-desorption cycle. The preferred column height of adsorption column 1 is 5cm-30cm.

[0044] The upper and lower surfaces are covered with mesh caps 2, which can retain the lithium ion sieve within the adsorption column 1 while ensuring that the liquid can flow smoothly from top to bottom or bottom to top through the adsorption column 1. The column material of the adsorption column 1 can be a lightweight and strong acid and alkali corrosion resistant material, such as polytetrafluoroethylene.

[0045] Since the lithium ion sieve consists of particles with a diameter of 0.3mm-2mm and a density similar to that of water, it can be freely dispersed in the liquid within the adsorption column 1. This ensures that the liquid can fully contact the lithium ion sieve when flowing through the adsorption column 1 without forming runoff. At the same time, even at high flow rates, such as 100 times or more of the space volume per hour, no pressure drop will form between the upper and lower surfaces of the adsorption column 1.

[0046] Among them, the lithium-ion sieve filling of a single adsorption column 1 is very simple due to its small size. When replacing the lithium-ion sieve, it is only necessary to disassemble each adsorption column 1 and then disassemble / fill the lithium-ion sieve separately, or replace the original adsorption column 1 with an adsorption column 1 that has been filled with a new lithium-ion sieve.

[0047] The adsorption column 1 is mounted on the lithium-ion sieve tray 3 during use. The lithium-ion sieve tray 3 has the following structure: Figure 2 As shown, the tray 3 is connected to the cover 2 of the adsorption column 1 via a threaded or snap-fit ​​connection. For example, various water pumps required for adsorption-desorption can be connected to the tray 3. For example, with the adsorption columns 1 evenly distributed, connecting the water distributor to the tray can ensure that the liquid flow is uniform and normal within each adsorption column 1. The absolute amount of lithium ion sieves in a single adsorption column 1 is relatively small, which is beneficial for the uniform distribution of lithium ion sieves.

[0048] Two trays 3 and the corresponding number of adsorption columns 1 in between can form an adsorption combination. When an adsorption tower has multiple adsorption combinations, a single cycle can use one, two, three, or even multiple adsorption combinations to adsorb the same portion of brine simultaneously.

[0049] If an adsorption tower has only one adsorption combination, it can be partitioned on the tray 3 so that the effluent from part of the adsorption column 1 is used as the influent from another part of the adsorption column 1. This allows the adsorption columns 1 to be used in series. With the addition of an appropriate amount of desorption acid, the lithium ion concentration in the desorption liquid can be increased.

[0050] Due to the high adsorption efficiency and capacity of lithium-ion sieves, the adsorption and desorption performance of each cycle is not very consistent, leading to differences in adsorption efficiency and lithium concentration in the desorbate between consecutive cycles. In contrast, the adsorption combination designed in this application yields adsorption tail liquid and desorbate that are the average values ​​of those obtained from multiple adsorption columns 1. This averaging effect effectively bridges the previously wider distribution of adsorption efficiency and lithium concentration in the desorbate, better meeting the requirements of industrial production for feedstock solutions.

[0051] Among them, since the adsorption columns 1 are all hexagonal in structure, the overall strength of the adsorption combination formed by them and the tray 3 is much higher than that of the bed layer of a traditional adsorption tower.

[0052] Example 1 This embodiment provides a method for extracting lithium from chloride-type salt lake brine. The adsorption tower described in this application is used. The adsorption column has a side length of 5cm on the upper and lower surfaces and a height of 50cm. A single layer contains 217 adsorption columns and is loaded with 669L of lithium ion sieves, meaning that the amount of lithium ion sieves loaded in each adsorption column is 95% of the volume of the adsorption column.

[0053] Table 1. Components of the original brine of Chaka Salt Lake

[0054] The raw brine from the Chaka Salt Lake was introduced into the adsorption tower. Lithium ions in the brine were adsorbed by a lithium-ion sieve at a flow rate of 50 times the space volume per hour. After 5 hours of adsorption, the flow of raw brine was stopped. The lithium-ion sieve in the adsorption tower was then washed with deionized water. During washing, an ultrasonic generator and a vibrating motor were activated, with the ultrasonic generator frequency controlled at 50 kHz and the vibrating motor frequency at 20 Hz. The deionized water flow rate was 30 times the space volume per hour. Washing continued until the conductivity of the outflowing wash water reached 700 μS. After washing, the ultrasonic generator and vibrating motor were turned off, and an acid solution (using H₂O) was introduced. + The adsorption was carried out using a 2 mol / L sulfuric acid solution; the adsorption-desorption cycle was repeated 10 times, and the experimental results are shown in Table 2.

[0055] Table 2 Lithium extraction test results

[0056] Adsorption efficiency = (1 - Lithium ion concentration in the adsorption tail liquid / Original halide lithium ion concentration) * 100% The method for preparing the lithium-ion sieve in this embodiment includes the following steps: (1) Preparation of lithium-ion precursors: Step 1: Mix 10g of manganese carbonate and 1.5g of magnesium carbonate, and then ball mill them to the micron level.

[0057] Step 2: Sinter at 800℃ for 48 hours in air atmosphere.

[0058] 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. Step 4: Sinter the powder obtained in step 3 at 450°C for 48 hours in air atmosphere to obtain lithium ion sieve precursor.

[0059] (2) Mix 10g of lithium ion sieve precursor, 4g of polyvinylidene fluoride, 0.75g of sodium linear alkylbenzene sulfonate and 30g of N-methylpyrrolidone obtained in step (1), and stir at 4000rpm for 4h at 60℃ to obtain a slurry.

[0060] (3) Granulation: Transfer the slurry to a container with holes at the bottom. The holes are 1 mm in diameter. Pressurize the slurry with 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.

[0061] (4) Sieve to obtain a lithium ion sieve with a diameter range of 0.3 mm to 2 mm.

[0062] Example 2 This embodiment provides a method for extracting lithium from chloride-type salt lake brine. The adsorption tower described in this application is used. The adsorption column has a side length of 5cm on the upper and lower surfaces and a height of 50cm. A single layer contains 217 adsorption columns and is loaded with 352L of lithium ion sieves. That is, the amount of lithium ion sieves loaded in each adsorption column is 50% of the volume of the adsorption column.

[0063] The raw brine from the Chaka Salt Lake was introduced into the adsorption tower. Lithium ions in the brine were adsorbed by lithium-ion sieves at a flow rate of 15 times the space volume per hour. After 10 hours of adsorption, the flow of raw brine was stopped. Deionized water was then introduced to wash the lithium-ion sieves in the adsorption tower. During washing, an ultrasonic generator and a vibrating motor were activated, with the ultrasonic generator frequency controlled at 100 kHz and the vibrating motor frequency at 50 Hz. The deionized water flow rate was 30 times the space volume per hour. Washing continued until the conductivity of the outflowing wash water reached 700 μS, using 840 L of water. After washing, the ultrasonic generator and vibrating motor were turned off, and acid solution (using H₂O) was introduced. + The adsorption was carried out using a 2 mol / L sulfuric acid solution; the adsorption-desorption cycle was repeated 10 times, and the experimental results are shown in Table 3.

[0064] Table 3 Lithium extraction test results

[0065] This embodiment provides a method for preparing a lithium-ion sieve, including the following steps: (1) Preparation of lithium-ion sieve precursor: Step 1: Mix 10g of manganese carbonate and 0.5g of magnesium carbonate, and then ball mill them to the micron level.

[0066] Step 2: Sinter at 700℃ for 1 hour in air atmosphere.

[0067] 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. Step 4: Sinter the powder obtained in step 3 at 350°C for 1 hour in air atmosphere to obtain lithium ion sieve precursor.

[0068] (2) Mix 10g of lithium ion sieve precursor, 2.5g of polyvinylidene fluoride, 0.75g of sodium linear alkylbenzene sulfonate and 15g of N-methylpyrrolidone obtained in step (1), and stir at 500rpm for 1h at 30℃ to obtain a slurry.

[0069] (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.

[0070] (4) Sieve to obtain a lithium ion sieve with a diameter range of 0.3 mm to 2 mm.

[0071] Example 3 This embodiment provides a method for extracting lithium from chloride-type salt lake brine. The adsorption tower described in this application is used. The adsorption column has a side length of 1 cm on the upper and lower surfaces and a height of 10 cm. A single layer contains 241 adsorption columns and is loaded with 5.6 L of lithium ion sieves. That is, the amount of lithium ion sieves loaded in each adsorption column is 90% of the volume of the adsorption column.

[0072] The raw brine from the Chaka Salt Lake was introduced into the adsorption tower. Lithium ions in the brine were adsorbed by a lithium ion sieve at a flow rate of 200 times the space volume per hour. After 0.5 hours of adsorption, the flow of raw brine was stopped. Deionized water was then introduced to wash the lithium ion sieve in the adsorption tower. During washing, an ultrasonic generator and a vibrating motor were activated, with the ultrasonic generator frequency controlled at 150 kHz and the vibrating motor frequency at 100 Hz. The deionized water flow rate was 30 times the space volume per hour. Washing continued until the conductivity of the outflowing wash water reached 700 μS. After washing, the ultrasonic generator and vibrating motor were turned off, and acid solution (using H2O) was introduced. + The adsorption was performed using a 2 mol / L sulfuric acid solution; the adsorption-desorption cycle was repeated 10 times. The experimental results are shown in Table 4. Table 4 Lithium extraction test results

[0073] The method for preparing the lithium-ion sieve in this embodiment includes the following steps: (1) Preparation of lithium-ion sieve precursor: Step 1: Mix 10g of manganese carbonate and 3g of magnesium carbonate, then ball mill to the micron level.

[0074] Step 2: Sinter at 900℃ for 72 hours in air atmosphere.

[0075] 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. Step 4: Sinter the powder obtained in step 3 at 500°C for 72 hours in air atmosphere to obtain lithium ion sieve precursor.

[0076] (2) Mix 10g of lithium ion sieve precursor, 10g of polyvinylidene fluoride, 0.6g of sodium linear alkylbenzene sulfonate and 80g of N-methylpyrrolidone obtained in step (1), and stir at 8000rpm for 6h at 80℃ to obtain a slurry.

[0077] (3) Granulation: Transfer the slurry to a container with holes at the bottom. The holes are 2 mm in diameter. Pressurize the slurry with air at 1 MPa above it. The slurry falls into the water pool below under the action of gravity and pressure, thus obtaining the shaped granules.

[0078] (4) Sieve to obtain a lithium ion sieve with a diameter range of 0.3 mm to 2 mm.

[0079] Example 4 The method for lithium extraction from chloride-type brine in this embodiment is basically the same as that in Example 1, except that the preparation method of the lithium ion sieve in this embodiment includes the following steps: (1) Preparation of lithium-ion sieve precursor: 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 the sintered powder with 5g of lithium hydroxide monohydrate, and perform a hydrothermal reaction at 0.2MPa and 130℃ for 24h. Step 4: Sinter the powder obtained in step 3 at 400°C for 24 hours in air atmosphere to obtain lithium ion sieve precursor.

[0082] (2) Mix 10g of lithium ion sieve precursor, 2.8g of polyvinylidene fluoride, 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.

[0083] (3) Granulation: The slurry is transferred to a container with holes at the bottom. The holes are 0.08 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.

[0084] (4) Sieve to obtain a lithium ion sieve with a diameter range of 0.3 mm to 2 mm.

[0085] Example 5 The method for lithium extraction from chloride-type brine in this embodiment is basically the same as that in Example 1, except that the preparation method of the lithium ion sieve in this embodiment includes the following steps: This embodiment provides a method for preparing a lithium-ion sieve, including the following steps: (1) Preparation of lithium-ion sieve precursor: Step 1: Mix 10g of manganese carbonate and 2g of magnesium sulfate, then ball mill to the micron level.

[0086] Step 2: Sinter at 850℃ for 60 hours in air atmosphere.

[0087] 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. Step 4: Sinter the powder obtained in step 3 at 450°C for 60 hours in air atmosphere to obtain lithium ion sieve precursor.

[0088] (2) Mix 10g of lithium ion sieve precursor, 5g of polyvinylidene fluoride, 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 slurry.

[0089] (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.

[0090] (4) Sieve to obtain a lithium ion sieve with a diameter range of 0.3 mm to 2 mm.

[0091] Example 6 This embodiment is basically the same as Embodiment 1, except that in this embodiment: after the first adsorption, a first desorption is performed, and during the first desorption, an acid solution (using H+) is introduced. + The solution (containing 2 mol / L sulfuric acid) is used for desorption to obtain the first desorption solution; then a second adsorption and a second desorption are performed. During the second desorption, acid is added to the first desorption solution to remove H+. + The concentration was adjusted to 2 mol / L, and the adjusted first desorption solution was used to desorb lithium ions from the sieve to obtain the second desorption solution. Then, a third adsorption and a second desorption were performed. During the third desorption, acid was added to the second desorption solution to remove H+. + The concentration was adjusted to 2 mol / L, and the adjusted second desorption solution was used to desorb lithium ions from the sieve to obtain the third desorption solution. All the above steps constituted one cycle, and the third desorption solution was the final desorption solution. The above cycle was performed 10 times (equivalent to 30 adsorption-desorption processes), and the experimental results are shown in Table 5.

[0092] Table 5 Lithium concentration in the desorption solution

[0093] Example 7 This embodiment is basically the same as Embodiment 2, except that the adsorption tower in this embodiment does not include an ultrasonic generator and a oscillating motor. In this embodiment, deionized water is used for washing at a flow rate of 30 times the space volume / hour until the conductivity of the outflowing wash water is 700 μs, using 1600 L of water.

[0094] Comparative Example 1 This comparative example provides a method for lithium extraction from chloride-type brine in salt lakes, which is basically the same as Example 1, except that an existing adsorption tower is used. The cylindrical adsorption column bed has a radius of 20 cm on both the upper and lower surfaces and a height of 100 cm, and is loaded with the same 635L lithium ion sieve as in Example 1. The test results are shown in Table 6.

[0095] Table 6 Lithium Extraction Test Results

[0096] As can be seen, Example 1 has a significantly higher adsorption efficiency than Comparative Example 1, and the stability of the adsorption efficiency and the stability of the lithium ion concentration in the desorption solution are significantly better.

[0097] Comparative Example 2 This comparative example is basically the same as Example 1, except that the preparation method of the lithium ion sieve in this comparative example is as follows: (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.

[0098] (2) Mix 10g of lithium ion sieve precursor, 4g of polyvinylidene fluoride, 0.75g of sodium linear alkylbenzene sulfonate and 30g of N-methylpyrrolidone obtained in step (1), and stir at 4000rpm for 4h at 60℃ to obtain a slurry.

[0099] (3) Granulation: Transfer the slurry to a container with holes at the bottom. The holes are 1 mm in diameter. Pressurize the slurry with 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.

[0100] The test results of this comparative method for lithium extraction from chloride-based brine in salt lakes are shown in Table 7.

[0101] Table 7 Lithium Extraction Test Results

[0102] 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 method for lithium extraction from chloride-type salt lake brine, characterized in that, The steps include the following: A lithium-ion sieve is loaded into an adsorption tower, and chloride-type brine from the salt lake is passed into the adsorption tower. The lithium-ion sieve adsorbs lithium ions in the chloride-type brine. After adsorption is completed, the flow of chloride-type brine from the salt lake is stopped, and the lithium-ion sieve is washed with water to desorb the ions. The adsorption-desorption cycle is repeated to extract lithium. The adsorption tower includes a main body, and multiple adsorption columns are arranged in parallel inside the tower cavity of the main body; The raw materials of the lithium-ion sieve, by mass percentage, include: 5-40% lithium-ion sieve precursor, 5-10% binder, 0.3-3% surfactant, and the balance being 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.

2. The method for lithium extraction from chloride-type brine in salt lakes 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; (4) The adhesive is one or more of polyvinyl chloride, polyvinylidene fluoride, and polytetrafluoroethylene; (5) 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; (6) The solvent is one or more of N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide.

3. The method for lithium extraction from chloride-type brine in salt lakes according to claim 1, characterized in that, In the method for preparing the lithium-ion sieve precursor, step 1 has at least one of the following features: (1) The mass ratio of the magnesium salt to the manganese-containing compound is (5-30):100; (2) The temperature of the first sintering is 700-900℃ and the time is 1-72h; (3) The mixture of the magnesium salt and the manganese-containing compound is ball-milled until the particle size reaches the micron level.

4. The method for lithium extraction from chloride-type brine in salt lakes according to claim 1, characterized in that, In the method for preparing the lithium-ion sieve precursor, step 2 has at least one of the following features: 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; C. The secondary sintering temperature is 350-500℃, and the time is 0.5-72h.

5. The method for lithium extraction from chloride-type brine in salt lakes according to any one of claims 1-4, characterized in that, The preparation method of the lithium-ion sieve 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.

6. The method for lithium extraction from chloride-type brine in salt lakes according to claim 5, 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.

7. The method for lithium extraction from chloride-type brine in salt lakes according to claim 5, 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.

8. The method for lithium extraction from chloride-type brine in salt lakes according to claim 7, characterized in that, The aperture of the hole is 0.05~2mm, and the pressure of the gas is 0.05~1MPa.

9. The method for lithium extraction from chloride-type brine in salt lakes according to any one of claims 1-4, characterized in that, Each of the adsorption columns has a cover with mesh on both the upper and lower end faces. The cover can prevent the lithium ion sieve inside the adsorption column from overflowing while allowing liquid to pass through.

10. The method for lithium extraction from chloride-type brine in salt lakes according to claim 9, characterized in that, The amount of lithium-ion sieves loaded in each adsorption column is 50-95% of the column volume.

11. The method for lithium extraction from chloride-type brine in salt lakes according to claim 9, characterized in that, The flow rate of chloride-type salt lake brine into the adsorption tower is 2 to 200 times the space volume per hour.

12. The method for lithium extraction from chloride-type brine in salt lakes according to claim 9, characterized in that, The adsorption tower also includes an ultrasonic generator; the ultrasonic generator is installed in both the top cavity and the bottom cavity of the tower.

13. The method for lithium extraction from chloride-type brine in salt lakes according to claim 12, characterized in that, When washing with water, start the ultrasonic generator and control the frequency of the ultrasonic generator to 10~150kHz.

14. The method for lithium extraction from chloride-type brine in salt lakes according to claim 9, characterized in that, The adsorption tower also includes a vibrating motor; the vibrating motor is located outside the main body and is connected to the outer wall of the main body via a rigid rod.

15. The method for lithium extraction from chloride-type brine in salt lakes according to claim 14, characterized in that, When washing, start the vibrating motor and control the frequency of the vibrating motor to 5~100Hz.

16. The method for lithium extraction from chloride-type brine in salt lakes according to claim 9, characterized in that, The adsorption column satisfies at least one of the following conditions: (1) The end face of each of the adsorption columns is a regular hexagonal structure, and two adjacent adsorption columns are seamlessly spliced ​​together; (2) The side length of each adsorption column ranges from 0.5cm to 5cm; (3) The height of each adsorption column ranges from 5cm to 50cm; (4) Multiple adsorption columns are provided in the tower cavity along the height direction of the main body, and multiple adsorption columns in the same layer form an adsorption combination.

17. The method for lithium extraction from chloride-type brine in salt lakes according to claim 16, characterized in that, The adsorption tower also includes a tray, and the top and bottom surfaces of the adsorption assembly are provided with the tray; the tray surface is provided with a plurality of mounting holes adapted to the shape of the end face of the adsorption column, and the end face of each adsorption column is inserted into the mounting hole.

18. The method for lithium extraction from chloride-type brine in salt lakes according to claim 16, characterized in that, The adsorption tower also includes a water distributor, which is located below the adsorption assembly and allows the liquid to flow evenly through each adsorption column in the same adsorption assembly.

19. The method for lithium extraction from chloride-type brine in salt lakes according to claim 1, characterized in that, During the first desorption, H+ was introduced. + The first desorption solution is obtained by desorption with an acid solution of concentration of 1~2 mol / L; during the second desorption, acid is added to the first desorption solution to remove H+. + The concentration was adjusted to the initial level, and the adjusted first desorption solution was used to desorb lithium ions from the sieve to obtain the second desorption solution. For the third desorption, acid was added to the second desorption solution to remove H+. + The concentration was adjusted to the initial level, and the lithium-ion sieve was desorbed using the adjusted second desorption solution to obtain the third desorption solution.

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