CN116443899B

CN116443899B - Method for preparing lithium hydroxide by using lithium-rich liquid obtained by lithium ion sieve adsorption method

Info

Publication number: CN116443899B
Application number: CN202310286398.9A
Authority: CN
Inventors: 胡羽
Original assignee: Lisi Shanghai Material Technology Co ltd
Current assignee: Lisi Shanghai Material Technology Co ltd
Priority date: 2023-03-22
Filing date: 2023-03-22
Publication date: 2024-04-30
Anticipated expiration: 2043-03-22
Also published as: CN116443899A

Abstract

The invention belongs to the technical field of lithium extraction in salt lakes, and particularly relates to a method for preparing lithium hydroxide by using lithium-rich liquid obtained by a lithium ion sieve adsorption method, which has the advantage of low energy consumption. According to the method for preparing lithium hydroxide by utilizing the lithium-rich liquid obtained by the lithium ion sieve adsorption method, the multi-layer adsorption tower for efficiently extracting lithium is utilized for carrying out adsorption method lithium extraction treatment, and sodium modified zeolite adsorbent is adopted for carrying out sodium ion adsorption treatment on the lithium-rich liquid, so that the lithium yield is higher in the whole lithium extraction process, the whole treatment process hardly generates phase change, other processes except the final evaporation crystallization process are carried out in the modes of low-energy filtration, pumping and the like, the liquid can be recycled, and the method has the advantages of environmental protection and low energy consumption.

Description

Method for preparing lithium hydroxide by using lithium-rich liquid obtained by lithium ion sieve adsorption method

Technical Field

The invention belongs to the technical field of lithium extraction in salt lakes, and particularly relates to a method for preparing lithium hydroxide by using lithium-rich liquid obtained by a lithium ion sieve adsorption method, which has the advantage of low energy consumption.

Background

Lithium is the lightest metal in the world, also called "energy metal", and is an indispensable raw material for supporting the development of new energy automobile industry. With the increasing development of new energy technologies, the global demand for lithium is increasing. Therefore, the development and utilization of lithium resources have become a hotspot for global research and development, and are receiving a great deal of attention. The lithium resources in China are rich, and more than 70% of the lithium resources belong to the lithium resources in the salt lake. At present, reported methods for extracting lithium from salt lake brine mainly comprise an adsorption method, a precipitation method, an extraction method, a membrane separation method, a calcination method and the like. The method is characterized in that Li ⁺ in the brine is adsorbed by a lithium ion sieve adsorbent, then Li ⁺ is desorbed by a desorption liquid, and the obtained lithium-rich liquid is subjected to post-treatment operations such as purification and the like. Lithium ion sieve adsorption is used for extracting lithium as an emerging technology, and the produced lithium-rich liquid is different in composition from the lithium-rich liquid obtained by the traditional ore method. At present, the market has little research on how to prepare a marketized lithium product from a lithium-rich liquid generated after lithium extraction by a lithium ion sieve adsorption method, and particularly how to prepare a marketized lithium hydroxide product from the lithium-rich liquid obtained by the lithium ion sieve adsorption method with low cost and low energy consumption.

In the lithium ion sieve adsorption process, the volume of the existing adsorption tower is generally larger and is a few meters high, when the manganese-based and titanium-based adsorbents with high adsorption speed and adsorption efficiency are used, no matter whether brine is fed in from top to bottom or fed in from top to bottom, in the adsorption process, the adsorbents in the adsorption tower are in a state that the adsorbents cannot be adsorbed again after being saturated or in a state that the adsorbents are not saturated but contacted and hardly contain lithium in most of the time, so that the efficiency of the whole adsorption process is low.

In addition, after lithium ions are adsorbed from salt lake brine by using a lithium ion sieve, the adsorbed lithium ions are required to be resolved into a resolving solution by a resolving process. The resolved solution is concentrated and then added with sodium hydroxide to adjust the pH value to be more than 12, calcium and magnesium ions can be filtered, and the lithium-rich solution mainly contains lithium ions, sodium ions (a large amount of sodium ions are added when the pH value is adjusted) and sulfate ions. The lithium-rich liquid is further concentrated with great difficulty and high energy consumption due to the existence of a large amount of sodium ions, and the effect of final crystallization and lithium precipitation is also affected. In the prior art, sodium ions of the lithium-rich liquid of the sulfuric acid system can be removed through mirabilite crystallization after freezing, but the energy consumption is higher, partial lithium ion loss can be caused during solid-liquid separation, sodium ions of the lithium-rich liquid of the chloride system cannot be removed, and a large amount of lithium ions are lost along with the mother liquor only after crystallization and lithium precipitation are circulated or discharged along with the mother liquor. Therefore, how to remove the sodium ions in the lithium-rich liquid in a manner with low energy consumption and no loss of lithium ions is also a great difficulty faced in the field.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to provide a method for preparing lithium hydroxide by using the lithium-rich liquid obtained by the lithium ion sieve adsorption method, and the method has the advantages of low energy consumption, low cost and good economic benefit.

In order to solve the technical problems, the method for preparing lithium hydroxide by using the lithium-rich liquid obtained by the lithium ion sieve adsorption method is characterized by comprising the following steps:

(1) Conveying salt lake brine to be treated into a multi-layer adsorption tower provided with a lithium ion sieve adsorbent for lithium extraction treatment, analyzing by taking sulfuric acid as an analysis liquid to obtain a sulfate solution, and concentrating to obtain an enriched sulfate solution;

(2) Adjusting the pH value of the enriched sulfate solution to 11-12.5, collecting a liquid part through solid-liquid separation to obtain a lithium-enriched liquid, and respectively carrying out boron removal, calcium removal, magnesium removal and manganese removal treatment on the lithium-enriched liquid;

(3) The lithium-rich liquid is contacted with a sodium modified zeolite adsorbent to carry out sodium ion adsorption treatment, so as to obtain a low-sodium lithium-rich liquid;

(4) Concentrating the low-sodium lithium-rich liquid, evaporating and crystallizing, and collecting precipitated lithium hydroxide monohydrate crystal by solid-liquid separation.

Specifically, in the step (2), the pH of the enriched sulfate solution is adjusted to 11-12.5, more preferably to 12.0, by adding sodium hydroxide.

Specifically, in the step (4), the method further comprises a step of adding a solution part obtained by solid-liquid separation into the lithium-rich liquid and mixing, wherein the solution part and the lithium-rich liquid have similar components and proportions.

Specifically, in the step (4), the step of recrystallizing the lithium hydroxide monohydrate crystal is further included, namely, the lithium hydroxide monohydrate crystal is dissolved in water and then recrystallized, so that the quality of the lithium hydroxide monohydrate is improved, and a battery-grade lithium hydroxide product is obtained.

In order to realize efficient lithium extraction of salt lake brine, the method adopts an optimally designed multi-layer adsorption tower to carry out lithium ion adsorption sieve lithium extraction treatment.

Specifically, the multilayer adsorption tower at least comprises:

The main body is provided with a hollow tower cavity, and the tower cavity is provided with a water inlet and a water outlet;

adsorption dishes are arranged in the tower cavity at intervals along the height direction of the main body, and each adsorption dish is filled with an adsorbent;

the first permeable structure is arranged in the tower cavity and positioned between the two upper and lower adjacent adsorption dishes, and has a permeable state allowing water to pass through and a water isolation state limiting the water to pass through.

Further, the first water permeable structure comprises a first partition plate and a second partition plate which are arranged in a stacked mode, and a plurality of water permeable holes are formed in the plate surfaces of the first partition plate and the second partition plate; the first partition plate can rotate around the axis of the first partition plate so that the water permeable holes on the first partition plate and the water permeable holes on the second partition plate are mutually overlapped or mutually staggered.

Further, the first partition plate and the second partition plate are obliquely arranged on the horizontal plane, so that a liquid level lowest point and a liquid level highest point are formed between two adjacent first water permeable structures; each liquid level minimum point is provided with a liquid inlet and a liquid outlet, and each liquid level maximum point is provided with a liquid outlet.

Further, the adsorption vessel is of a columnar structure, a first filter screen is arranged on the top surface of the adsorption vessel, and a second filter screen is arranged on the bottom surface of the adsorption vessel; the first filter screen and the second filter screen are suitable for limiting the leakage of the adsorbent in the adsorption vessel.

Further, the adsorption tower further comprises a second water permeable structure which is arranged on the bottom surface of the adsorption vessel and is positioned on one side of the second filter screen opposite to the first filter screen, wherein the second water permeable structure is in a water permeable state allowing water to pass through and in a water isolation state limiting the water to pass through.

Further, a preset interval is reserved between the second water permeable structure and the second filter screen, and the range of the preset interval is 1mm-2mm.

Further, the bottom surface of absorption dish is provided with the ring, fork truck passes through the ring is right absorption dish removes.

Further, edge positions of the top surface and the bottom surface of the adsorption vessel are respectively provided with a spreading edge, and the spreading edges extend towards a direction away from the center of the adsorption vessel and are suitable for fixing the adsorption vessel in the tower cavity through the spreading edges.

Further, a door body is arranged on the side wall of the tower cavity and is suitable for taking the adsorption vessel in the tower cavity through the door body.

Further, the bottom of the main body is of a conical structure, and the water inlet and the water outlet are both positioned on the side wall of the conical structure.

Specifically, in the step (1), after the multi-layer adsorption tower is used for adsorbing and extracting lithium, sulfuric acid is used as an analysis solution, and sulfate solution with the concentration of 3-4g/L of lithium ions, 3-4g/L of sodium ions, 0.2-0.5g/L of potassium ions, 0.1-0.5g/L of magnesium ions, 0.05-0.2g/L of calcium ions and 0.01-0.1g/L of boron ions can be obtained.

Specifically, in the step (1), the concentration step includes, but is not limited to, reverse osmosis, etc., and the sulfate solution after the lithium extraction may be concentrated to about 10g/L of the concentration of lithium ions, and the sulfate solution is enriched with other cations correspondingly.

Specifically, in the step (2), sodium hydroxide is added to adjust the solution to ph=12.0, and then the solution is filtered and centrifuged, so that a lithium-rich solution with a lithium ion concentration of about 10g/L can be obtained, and the lithium loss during this process is about 0.5%.

Specifically, in the step (2), according to the ion concentration of the lithium-rich solution, the boron-rich solution, the calcium-rich solution, the magnesium-rich solution and the manganese-rich solution are subjected to selective impurity removal treatment by using boron-rich, calcium-rich, magnesium-rich and manganese-rich resins, wherein the lithium ion concentration of the obtained lithium-rich solution is about 10g/L, the magnesium ion concentration is less than 1ppm, the calcium ion concentration is less than 1ppm, the boron concentration is less than 1ppm, and the manganese ion concentration is less than 0.1ppm.

Specifically, in order to further reduce the sodium ion concentration in the lithium-rich liquid, the invention selectively enables the lithium-rich liquid to be contacted with a sodium modified zeolite adsorbent for sodium ion adsorption treatment so as to reduce the sodium ion concentration in the lithium-rich liquid.

The invention provides a sodium modified zeolite adsorbent, which is prepared by taking analcite as a raw material and carrying out modification treatment on saturated sodium sulfate.

Alternatively, the modification treatment is to boil the analcite in a saturated sodium sulfate solution for 2-4 hours.

Optionally, the retrofitting process is repeated 3-6 times, and the turbid liquid is poured off after each retrofitting process is completed.

Optionally, the dosage ratio of the saturated sodium sulfate solution to the analcite is 3-20mL/g.

Optionally, the analcite has a particle size of 30-40 mesh.

Specifically, in the step (3), in the sodium ion adsorption step, the sodium modified zeolite adsorbent is used for carrying out adsorption treatment on the lithium-rich liquid.

Optionally, the lithium-rich liquid is contacted with the sodium modified zeolite adsorbent at a flow rate of 1-5 times of the volume/hour of the adsorbent for 2-5 hours to obtain the low-sodium lithium-rich liquid.

Optionally, the adsorption temperature is 10-60 ℃.

Optionally, the method further comprises subjecting the adsorbed sodium modified zeolite adsorbent to a resolving treatment;

optionally, adopting a solution containing 0.05-0.3mol/L lithium sulfate with the pH value of 1.5-2 for resolution treatment; optionally, the analysis treatment is carried out by adopting a lithium ion sieve analysis solution.

Optionally, the lithium ion sieve analysis solution is contacted with the sodium modified zeolite adsorbent after adsorption at a flow rate of 5-10 times of the volume of the adsorbent per hour, and the contact time is 0.5-1h.

Specifically, the preparation of the sodium modified zeolite: grinding zeolite to 30-40 mesh, boiling in saturated sodium sulfate solution for 2-4 hr, pouring out turbid liquid, repeating for 3-6 times, modifying zeolite, oven drying, and placing in adsorption device.

Specifically, as shown in fig. 7, a detailed operation method for reducing the concentration of sodium ions in the lithium-rich liquid may be: the lithium-rich liquid with the concentration of lithium ion of about 10g/L, the concentration of sodium ion of more than 10g/L and the pH value of about 12.0 and the anions mainly being sulfate ions is passed through an adsorption tower filled with sodium modified zeolite adsorbent at the flow rate of 1-5 times of the volume of the adsorbent per hour after being heated at normal temperature or for 2-5 hours, and then the adsorption is completed. Because the adsorption selectivity of the sodium modified zeolite to hydrated sodium ions is far higher than that of the hydrated lithium ions at the temperature of 10-60 ℃ and the pH value of 11-12.5, the concentration of lithium ions in the sodium-removing lithium-rich liquid after adsorption is still about 10g/L, and the concentration of sodium ions is not higher than 5g/L. The lithium-rich liquid can be crystallized and precipitated by simple concentration.

Since sulfate, sodium ion and lithium ion are valuable ions, water washing is not needed, and sodium zeolite after adsorption can be directly analyzed. And (3) introducing a lithium sulfate solution with the pH of about 1.5-2.0 and a lithium ion sieve analysis solution with the pH of 0.05-0.3mol/L (namely, an analysis solution obtained by using sulfuric acid for analysis in a lithium extraction process of a salt lake by a lithium ion sieve adsorption method, hereinafter referred to as a lithium ion sieve analysis solution) into an adsorption tower, and then circularly analyzing at a flow rate of 5-10 times of the volume of the adsorbent per hour, wherein the analysis is completed for 0.5-1 hour. Because the concentration of lithium ions in the lithium ion sieve analysis solution is higher than that of sodium ions, and the selectivity of sodium modified zeolite to sodium ions hydrate and lithium ions hydrate in the environment with the pH value of 1.5-2.0 is not greatly different, a large amount of sodium ions are replaced by hydrogen ions and lithium ions from the zeolite. After zeolite analysis is completed, the lithium ion sieve analysis liquid becomes zeolite analysis liquid, wherein the concentration of lithium ions is reduced, the concentration of sodium ions is greatly increased, and the pH value is increased. The effective point in the sodium modified zeolite is occupied by hydrogen ions and lithium ions, the effective point is exchanged with sodium ions in the subsequent adsorption, and the lithium ions enter the lithium-rich liquid of the next round to be utilized.

After the zeolite desorption solution is obtained, the zeolite desorption solution and the lithium ion sieve desorption solution are mixed in a ratio of 1:1-1:5, and then the sodium zeolite after the adsorption is completed can be desorbed again. After the analysis is finished, the concentration of sodium ions in the zeolite analysis liquid is far higher than that of lithium ions, when the concentration of sodium ions in the zeolite analysis liquid is more than or equal to 10g/L, the zeolite analysis liquid is simply concentrated to the concentration of sodium ions of 30-40g/L and then frozen to below-10 ℃, a large amount of sodium sulfate decahydrate crystals are separated out, and the sodium sulfate decahydrate solid and the solution which can be continuously used in the analysis step after being diluted can be obtained through centrifugal separation. By the method, sodium ions continuously enriched in the system can be stripped out of the system, so that the system can be ensured to be circulated.

Typically, but not by way of limitation, sodium sulfate decahydrate may be produced by bipolar membrane electrodialysis to produce 0.5-2mol/L sulfuric acid solution, which may be used to desorb the lithium ion sieve adsorbent, and 0.5-2mol/L sodium hydroxide solution, which may be used to adjust the pH of the lithium ion sieve desorption solution after further concentration. So far, all impurities complete circulation in the system, and no external discharge exists. The lithium-sodium ratio in the lithium-rich liquid is improved to 2.5:1 to 3:1, and the subsequent concentration crystallization lithium precipitation process becomes very simple.

In the method, after the sodium ion adsorption treatment in the lithium-rich liquid is carried out by the sodium modified zeolite adsorbent, the concentration of lithium ions in the obtained low-sodium lithium-rich liquid is about 10g/L, the concentration of sodium ions is about 5g/L, the concentration of potassium ions is about 0.1-0.3g/L, the concentration of magnesium ions is less than 1ppm, the concentration of calcium ions is less than 1ppm, the concentration of boron is less than 1ppm, and the concentration of manganese ions is less than 0.1ppm.

Specifically, in the step (4), the concentration of lithium ions in the concentrated solution is about 30g/L, the concentration of sodium ions is about 15g/L and the concentration of potassium ions is about 0.3-1g/L by means of high-pressure reverse osmosis and the like; and evaporating and crystallizing the solution, and centrifugally separating to obtain solid lithium hydroxide monohydrate crystal.

According to the method for preparing lithium hydroxide by using the lithium-rich liquid obtained by the lithium ion sieve adsorption method, the multi-layer adsorption tower for efficiently extracting lithium is used for carrying out adsorption method lithium extraction treatment, so that the lithium yield is higher; and sodium ion adsorption treatment is carried out on the lithium-rich solution by adopting the sodium modified zeolite adsorbent, so that the sodium ions can be continuously removed from the high-sodium high-lithium solution by a low-energy-consumption and recyclable process, compared with the traditional freezing sodium removal method, the energy consumption can be greatly saved, and part of potassium is removed while sodium is removed, so that the cycle number of the mother solution is greatly increased, the yield of lithium is improved, the solid waste is reduced, and the subsequent concentration crystallization lithium precipitation process is very simple.

According to the method, the lithium yield is higher in the whole lithium extraction process, and the lithium yield in a single crystallization process is more than 97% in consideration of mother liquor recycling; besides, the whole treatment process almost does not generate phase change, other processes are carried out in modes of low-energy consumption filtration, pumping water and the like except the final evaporation crystallization process, liquid can be recycled, and only a small amount of impurity ions leave the system in a solid waste mode, so that the method has the advantages of environment-friendly process and low energy consumption.

According to the multi-layer adsorption tower, the plurality of adsorption vessels are arranged in the tower cavity at intervals, and the first water permeable structure can separate the adsorption vessels, so that the adsorption tower has different combination modes of independent adsorption of a single vessel and serial adsorption of a plurality of vessels, the effect of sufficient adsorption scale is ensured on the whole, and the operation efficiency of adsorbed brine can be kept as high as possible under various conditions such as different lithium concentrations, different temperatures and different flow rate working conditions.

The multi-layer adsorption tower disclosed by the invention ensures enough scale effect on the whole adsorption scale, fully considers the relative relation between the diffusion speed of the manganese-based/titanium-based adsorbent in the lithium ion sieve particles and the external flow speed under the conventional flow rate, forms an adsorption vessel for ensuring the continuous and efficient operation of the lithium ion sieve, and simultaneously ensures that the adsorbed brine can keep higher operation efficiency as much as possible under various conditions such as different lithium concentrations, different temperatures, different flow rate working conditions and the like through different combinations of single-vessel independent adsorption and multi-vessel serial adsorption.

The multilayer adsorption tower solves the problem that the adsorbent is difficult to fill and detach; the use efficiency of the adsorbent is improved; the dissolution loss of the adsorbent is reduced; the problem of design standardization of the adsorption tower is solved, and the adsorption tower can be designed in the same way for brine with different lithium concentrations; the problem of adsorption tower desorption liquid lithium concentration stability is solved, desorption liquid lithium concentration can be adjusted according to the demand.

After the sodium modified zeolite adsorbent disclosed by the invention is subjected to saturated sodium sulfate modification treatment, the analcite can show different adsorption selectivity on lithium ions and sodium ions in the lithium-rich solution under the conditions of different temperatures and different pH values, so that the sodium ions can be continuously removed from the high-sodium high-lithium solution by a low-energy-consumption recyclable process.

According to the sodium modified zeolite adsorbent, the sodium ions are continuously removed from a high-sodium high-lithium solution by using the performance of the sodium modified zeolite that the adsorption selectivity of the sodium modified zeolite to the lithium ions and the sodium ions in the lithium-rich solution is different under the conditions of different temperatures and different pH values, so that the lithium-sodium ratio in the lithium-rich solution can be improved to 2.5 by using a low-energy-consumption and recyclable process: 1 to 3:1, and the subsequent concentration crystallization lithium precipitation process becomes very simple.

Drawings

In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings, in which,

FIG. 1 is a schematic diagram of an adsorption column in an embodiment of the present invention;

FIG. 2 is a schematic diagram of an adsorption vessel in an adsorption column according to an embodiment of the present invention;

FIG. 3 is a schematic view of an insert ring in an adsorption column according to an embodiment of the present invention;

FIG. 4 is a schematic view of a first separator in an adsorption column according to an embodiment of the present invention;

FIG. 5 is a schematic view of a partial structure of an adsorption tower according to an embodiment of the present invention at the lowest liquid level point formed by a first water permeable structure;

FIG. 6 is a schematic view of a partial structure of an adsorption tower according to an embodiment of the present invention at the highest liquid level point formed by a first water permeable structure;

FIG. 7 is a flowchart illustrating an exemplary operation for reducing the concentration of sodium ions in a lithium-rich solution according to the present invention;

The reference numerals in the drawings are as follows: 1-main body, 2-door body, 3-first water permeable structure, 4-adsorption vessel, 5-edge, 6-first baffle, 7-water permeable hole, 8-first filter screen, 9-second filter screen, 10-second water permeable structure, 11-insert ring, 12-liquid inlet, 13-liquid outlet, 14-liquid level meter, 15-thermometer, 16-pH meter.

Detailed Description

The following examples are provided for a better understanding of the present invention and are not limited to the preferred embodiments described herein, but are not intended to limit the scope of the invention, any product which is the same or similar to the present invention, whether in light of the present teachings or in combination with other prior art features, falls within the scope of the present invention.

The specific experimental procedures or conditions are not noted in the examples and may be followed by the operations or conditions of conventional experimental procedures described in the literature in this field. The reagents or apparatus used were conventional reagent products commercially available without the manufacturer's knowledge.

Fig. 1 to 6 show the structure of a multi-layered adsorption tower used in the following examples of the present invention, in which the multi-layered adsorption tower of the above structure was used to perform the adsorption and lithium extraction operation of a lithium ion sieve.

FIG. 1 is a schematic diagram of an adsorption column in an embodiment of the present invention; FIG. 2 is a schematic diagram of an adsorption vessel in an adsorption column according to an embodiment of the present invention; as shown in fig. 1 and 2, this embodiment provides an adsorption tower, which at least includes: the main body 1 is provided with a hollow tower cavity, and the tower cavity is provided with a water inlet and a water outlet; adsorption dishes 4 are arranged in the tower cavity at intervals along the height direction of the main body 1, and each adsorption dish 4 is filled with an adsorbent; the first permeable structure 3 is arranged in the tower cavity and positioned between the two layers of adsorption dishes 4 which are vertically adjacent, and the first permeable structure 3 has a permeable state allowing water to pass through and a water isolation state limiting the water to pass through.

The adsorption tower that this embodiment provided is provided with a plurality of adsorption dishes 4 at the tower intracavity interval to first permeable structure 3 can separate each adsorption dish 4, makes the adsorption tower possess the independent absorption of single dish and the different combination modes of many dishes series connection absorption, has guaranteed sufficient absorption scale effect on the whole, also ensures that the brine that adsorbs can keep higher operating efficiency as far as under various circumstances such as different lithium concentration, different temperature, different flow rate operating mode.

FIG. 4 is a schematic view of a first separator in an adsorption column according to an embodiment of the present invention; as shown in fig. 4, the first water permeable structure 3 includes a first separator 6 and a second separator that are stacked, and a plurality of water permeable holes 7 are formed on the surfaces of the first separator 6 and the second separator; the first partition plate 6 can rotate around its own axis to make the water permeable holes 7 on the first partition plate 6 coincide with the water permeable holes 7 on the second partition plate or be staggered with each other.

Wherein the first partition plate 6 and the second partition plate are obliquely arranged on the horizontal plane respectively, so that a liquid level lowest point and a liquid level highest point are formed between two adjacent first water permeable structures 3; the lowest point of each liquid level is provided with a liquid inlet 12 and a liquid outlet 13, and the highest point of each liquid level is provided with the liquid outlet 13.

FIG. 3 is a schematic view of an insert ring in an adsorption column according to an embodiment of the present invention; as shown in fig. 3, the adsorption vessel 4 has a columnar structure, a first filter screen 8 is arranged on the top surface of the adsorption vessel 4, and a second filter screen 9 is arranged on the bottom surface of the adsorption vessel 4; the first screen 8 and the second screen 9 are adapted to limit the leakage of the adsorbent in the adsorption vessel 4.

The adsorption tower further comprises a second water permeable structure 10, the second water permeable structure 10 is arranged on the bottom surface of the adsorption vessel 4 and is positioned on one side of the second filter screen 9 opposite to the first filter screen 8, and the second water permeable structure 10 has a water permeable state allowing water to pass through and a water isolation state limiting the water to pass through.

Wherein, a preset interval is reserved between the second water permeable structure 10 and the second filter screen 9, and the range of the preset interval is 1mm-2mm.

Wherein, the bottom surface of absorption dish 4 is provided with the ring, and fork truck removes absorption dish 4 through the ring.

Wherein, the edge positions of absorption dish 4 top surface and bottom surface all are provided with and prolong limit 5, and the direction that extends of absorption dish 4 center was kept away from to limit 5 orientation is suitable for to fix absorption dish 4 in the tower intracavity through extending limit 5.

The side wall of the tower cavity is provided with a door body 2, and the door body 2 is suitable for taking the adsorption vessel 4 in the tower cavity.

Wherein, the bottom of main part 1 is the toper structure, and water inlet and delivery port all are located the lateral wall of toper structure.

Specifically, for example, the material of the main body 1 may be stainless steel or carbon steel, the lining may be made of an acid and alkali resistant material, and the outer surface of the main body 1 may be coated with a high-salt-vapor corrosion resistant coating.

For example, the adsorption column may have a cylindrical structure, the diameter of the body 1 may range from 0.1m to 10m, and the height may range from 0.5m to 20m.

For example, the interior of the body 1 may be divided into two to fifty layers, each of which is provided with an adsorption vessel 4 loaded with adsorbent.

For example, on one side outer wall of the main body 1, each layer may be provided with a rectangular door body 2 for loading the adsorption vessel 4 when the door body 2 is opened. After the adsorption vessel 4 is filled, the door body 2 is closed, and the barrel wall of the adsorption tower is sealed.

For example, each layer is uniform in structure outside the bottommost layer of the adsorption column. Wherein AB plane can set up the structure that is used for fixed absorption dish 4, for example, and the structure can be for setting up the rotatory buckle at the tower intracavity wall, also can set up annular arch in the inner wall in tower chamber and be used for fixing the part at the tower intracavity with absorption dish 4, and absorption dish 4 can't follow vertical direction motion after being installed, also can't rock about the tower intracavity simultaneously, is favorable to improving the adsorption effect.

The first water permeable structure 3 can be arranged at the CD plane in the tower cavity, the included angle between the first baffle 6 and the second baffle and the horizontal plane can be 1-45 degrees, preferably, the included angle is 1-10 degrees, so that the arrangement is favorable for liquid flow distribution and can be convenient for discharging pumped liquid.

For example, the first separator 6 and the second separator may each be formed of a thin circular plate with a plurality of circular water penetration holes 7. When the first partition plate 6 and the second partition plate are completely overlapped, water flow can pass through the first partition plate quickly, and water can be completely isolated after the first partition plate and the second partition plate are rotated for 1-30 degrees. The first baffle 6 and the second baffle can be made of stainless steel or polytetrafluoroethylene and the like, and the black solid hole in the center of the circle can be fastened with each other through a buckle. For example, the upper layer is the first partition plate 6, and the lower layer is the second partition plate, a magnet can be arranged on the rotatable circumference of the first partition plate 6 at intervals of 60 degrees, an electromagnet is correspondingly arranged at the corresponding position of the inner wall of the tower cavity at intervals of 60 degrees, and when 6 electromagnets are simultaneously electrified, the magnets on the whole first partition plate 6 can be attracted, and then the first partition plate 6 rotates clockwise or anticlockwise by an angle with the center as the axis, so that the water permeable holes 7 on the first partition plate 6 and the second partition plate are overlapped or staggered, and the water permeable state or the water blocking state is switched. For example, the first diaphragm 6 and the second diaphragm can be reset when the electromagnet is powered off by a spring connected between the first diaphragm 6 and the second diaphragm.

FIG. 5 is a schematic view of a partial structure of an adsorption tower according to an embodiment of the present invention at the lowest liquid level point formed by a first water permeable structure; as shown in fig. 5, for example, the position C is the lowest position of the liquid level of the upper layer of the first water permeable structure 3 after water is separated, and the position C is provided with a liquid inlet 12 and a liquid outlet 13, which can be respectively connected with the corresponding pump body through pipelines. The D position is the highest liquid level position of the lower layer of the first water permeable structure 3 after water is separated, and the D position is provided with a liquid outlet 13 which can be connected with a corresponding pump body through a pipeline.

FIG. 6 is a schematic view of a partial structure of an adsorption tower according to an embodiment of the present invention at the highest liquid level point formed by a first permeable structure, as shown in FIG. 6, for example, a liquid level gauge, a PH gauge 16, a conductivity gauge and a thermometer 14 may be disposed on the inner wall of the tower cavity near the D position; 15, so as to collect corresponding data, the collected data can be directly read from the outside of the main body 1, and the collected corresponding data can be sent to a central control system.

The bottom of the adsorption column is of a conical structure, and is provided with a water inlet and a water outlet which can be connected with a corresponding pump body through pipelines respectively.

For example, the adsorption vessel 4 may be made of stainless steel, polytetrafluoroethylene, or the like, and is resistant to acid and alkali. The height of the suction cup 4 may be 0.05m-3m. The width of the extension 5 around the upper and lower round surfaces of the adsorption vessel 4 can be 0.5cm-5cm, and the thickness range can be 1mm-20mm. So set up, the limit 5 not only can be convenient for fix the adsorption vessel 4, makes it keep the level after fixed, can also play certain water proof effect, ensures that all water that comes of upper and lower side passes through by the centre of adsorption vessel 4 for the water can fully contact with the adsorbent in the adsorption vessel 4.

For example, the upper surface of the adsorption vessel 4 is covered with a first filter 8 which can be opened, and the first filter 8 is fastened after the adsorption vessel 4 is loaded with the adsorbent so as to prevent the adsorbent from overflowing upwards from the adsorption vessel 4. The lower surface of the adsorption vessel 4 has three layers, and the first layer is a second filter screen 9 similar to the upper surface from top to bottom, and can be welded or adhered on the adsorption vessel 4 to prevent the adsorbent from overflowing downwards. The second layer is below the second filter screen 9, is the second water permeable structure 10, wherein, the second water permeable structure 10 can be the same with the first water permeable structure 3, is also two sheets, and is convenient for the adsorbent to permeate water in the state of permeating water at ordinary times, rotates to the state of isolating water when only taking out the adsorbent, and is convenient for the adsorbent to suck out/pour out together with water. The third layer is arranged below the second water permeable structure 10, and is an insert ring 11, and the insert ring 11 can be welded at the bottom of the adsorption vessel 4 for fixing and limiting the adsorption vessel 4 by a forklift and loading the adsorption vessel 4 into an adsorption tower. For example, the insert ring 11 may be two hollow rectangular cylinders which fit the shape of the suction cup 4, and when suction is placed in the tower cavity, displacement does not occur in the horizontal direction.

For example, the distance between the second sieve 9 and the second water permeable structure 10 is generally small but must be present, for example, it may be 1-2 mm. For the second water permeable structure 10, the radius of the first separator 6 on the upper layer can be slightly smaller than the inner diameter of the adsorption vessel 4, so that the first separator can rotate in the adsorption vessel 4, the second separator on the lower layer can be firmly connected with the lower surface of the adsorption vessel 4 in a welding, fastening or other manner and is flush with the lower surface of the adsorption vessel 4, and the joint of the second separator and the adsorption vessel 4 can be subjected to sealing treatment.

When the adsorption tower is used, the adsorption tower can be externally connected with a plurality of pump bodies and acid liquid tanks according to the design requirement of the adsorption tower so as to realize the requirements of liquid inlet and outlet, liquid storage and the like in the adsorption and desorption process.

The specific process is as follows:

Adsorbent unloading/loading:

When the adsorbent is unloaded, all the first water permeable structures 3 are firstly adjusted to be in a water permeable state, and water in the adsorption tower is emptied through a water outlet at the F position. The door body 2 on the outer wall of the lowest or highest layer of adsorption towers is opened, and the adsorption dishes 4 on the layer are taken out by a forklift. The operation is carried out layer by layer until all the suction cups 4 are taken out. The first filter screen 8 on the upper layer of all the adsorption vessels 4 is opened, and the first water permeable structure 3 on the lower layer of the adsorption vessels 4 is adjusted to a water-proof state. After filling each of the adsorption dishes 4 with water, the whole adsorbent was sucked out/poured out with a pump body. Because a layer of water is arranged between the second filter screen 9 and the second water permeable structure 10 below the adsorption vessel 4, the adsorbent can be easily sucked out/poured out without being adhered to the second filter screen 9. If new adsorbent is to be filled, the second water permeable structure 10 at the lower layer of the adsorption vessel 4 is adjusted to a water permeable state, and after a specified amount of new adsorbent is pumped in, the first filter screen 8 at the upper layer of the adsorption vessel 4 is buckled. After all the adsorption dishes 4 are loaded with new adsorbents, the adsorbents are loaded into the adsorption tower one by using a forklift, and then all the doors 2 on the outer wall of the main body 1 are closed, so that the loading of the adsorbents is completed.

Adsorption and desorption:

Because the lithium ion sieve adsorbent has strong adsorption capacity and high adsorption speed, a single group of circulation can simultaneously use one layer, two layers, three layers or even multiple layers of adsorption dishes 4 to adsorb the same part of brine according to different conditions such as the concentration of lithium in the adsorbed brine and the pH value. When only one layer of adsorption vessel 4 is used in single-group circulation, the first water permeable structure 3 below each layer of adsorption vessel 4 is adjusted to be in a water-proof state, the liquid inlet 12 above the C position is opened and connected with a brine tank, the liquid outlet 13 below the D position is opened and connected with an adsorption tail liquid tank, and each layer of adsorption vessel 4 is independently adsorbed. When the two-layer adsorption dishes 4 are recycled in a single group, every two adjacent adsorption dishes 4 are in a unit from the bottom of the adsorption tower, the first permeable structure 3 in the unit is adjusted to a permeable state, the first permeable structure 3 between the units is adjusted to a water isolation state, the liquid inlet 12 above the position C of the lower layer in the unit is opened and connected with a brine tank, and the liquid outlet 13 below the position D of the upper layer in the unit is opened and connected with an adsorption tail liquid tank. The method of recycling three or more suction cups 4 in a single set and so on.

During water washing, all the first water permeable structures 3 are adjusted to a water permeable state, so that water can flow through the adsorbents as much as possible, and a water saving effect is achieved. After water washing, the water outlet at the F position can be opened, so that the water washing water in the adsorption column is drained, the lithium concentration of the desorption liquid is improved, and the impurity ion concentration is reduced.

During desorption, the first water permeable structure 3 between each layer is adjusted to be in a water-proof state, the liquid inlet 12 at the C position is connected with the acid liquid tank through the pump body, and the liquid outlet 13 at the D position is also connected back to the same acid liquid tank, so that the cyclic desorption can be realized. After desorption is completed, the concentration of the desorption liquid lithium can be obtained in real time through a machine learning method for monitoring the concentration of the desorption liquid lithium on line. If the lithium concentration of the desorption solution fails to meet the requirement of the subsequent process design, for example, the lithium concentration of the subsequent process design is more than or equal to 2000ppm, and the lithium concentration of the desorption solution is only 1500ppm in real time, the liquid outlet 13 at the C position can be opened and communicated to another acid solution tank through a pump body, after the desorption solution is pumped to the other acid solution tank, a proper amount of concentrated acid is added into the acid solution tank for fully and uniformly mixing, the acid solution tank is connected to the adsorption vessel 4 layer which is not desorbed, and after the lithium ion concentration of the desorption solution is confirmed to meet the requirement, all the pump bodies of the part of the desorption solution are pumped into the desorption solution tank. After all the adsorption vessels 4 are distributed according to the process, the desorption liquid meeting the requirements as much as possible can be obtained in the shortest time, and meanwhile, the excessive acid flowing through each part of adsorbent is the smallest, so that the dissolution loss caused by acid leaching is greatly reduced.

Example 1

The diameter of the adsorption tower is 1.6 m, the height of the adsorption vessel is 30cm, 6 layers are added, the height of the adsorption tower is 3m, and the total weight of the loaded adsorbent is 3 cubic meters.

Unloading old adsorbent and filling new adsorbent, 2 people, a fork truck, a pump body, 0.8 hours for unloading old adsorbent, 1.5 hours for filling new adsorbent, and 2.3 hours in total.

And (3) absorbing 60 cubic meters of brine of a certain salt lake in a single cycle. Each layer is selected as a unit during adsorption, the total adsorption and desorption time is 2 hours, the recovery rate of lithium ions is 93%, the concentration of lithium ions in desorption liquid is 2g/L, and the manganese dissolution loss is 0.012%.

Comparative example 1

The diameter of the adsorption tower is 1.6 m, the height is 3.5 m, and the same adsorbent is loaded for 3 cubic meters.

Unloading old adsorbent and filling new adsorbent, 3 persons, a forklift, a pump body, 3.5 hours for unloading old adsorbent, 4 hours for filling new adsorbent, and 7.5 hours for total.

The single cycle adsorbs 60 cubic meters of the same salt lake brine. The total absorption and desorption time is 4 hours, the recovery rate of lithium ions is 89%, the concentration of lithium ions in desorption liquid is 1.5g/L, and the manganese dissolution loss is 0.035%.

Example 2

The diameter of the adsorption tower is 1.6 m, the height of the adsorption vessel is 30cm, 6 layers are added, the height of the adsorption tower is 3 m, and the total weight of the loaded adsorbent is 3 cubic meters. And (3) absorbing 240 cubic meters of salt lake brine in a single cycle. Every 3 layers are selected as a unit during adsorption, the total time for adsorption and desorption is 4 hours, the recovery rate of lithium ions is 95%, the concentration of lithium ions in desorption liquid is 2g/L, and the manganese dissolution loss is 0.007%.

Comparative example 2

The diameter of the adsorption tower is 1.6 m, the height is 3.5 m, and the same adsorbent is loaded for 3 cubic meters. Single cycle adsorption of 240 cubic meters of the same salt lake brine. The total absorption and desorption time is 5 hours, the recovery rate of lithium ions is 90%, the concentration of lithium ions in desorption liquid is 1.4g/L, and the manganese dissolution loss is 0.03%.

Example 3

In this example, the multi-layer adsorption tower in the above example 2 was used to extract lithium from the brine of the salt lake of Tibet JZCK by adsorption, and the sulfate solution was obtained by using sulfuric acid as the analytical solution for the analytical treatment. And (3) performing reverse osmosis concentration treatment on the sulfate solution, adding sodium hydroxide to adjust the pH value to be 12.0, performing filtration or centrifugation treatment, collecting a liquid part, and treating the lithium-rich solution through boron-removing, calcium-removing, magnesium-removing and manganese-removing resins to obtain the required lithium-rich solution.

The specific composition (g/L) of the lithium-rich liquid in this example was examined to include ：Li⁺10.325g/L、Na⁺12.672g/L、K⁺0.986g/L、Ca²⁺<0.001g/L、Mg²⁺<0.001g/L、pH＝12.

Example 4

This example uses the prepared sodium-modified zeolite adsorbent to perform a sodium ion adsorption treatment on the lithium-rich liquid of example 3 to reduce the concentration of sodium ions in the lithium-rich liquid.

Preparation of sodium modified zeolite: 40g of analcite (supplied by Lingshou Ningbo mineral products Co., ltd., hereinafter the same) was ground to 30-40 mesh, placed in 120ml of saturated sodium sulfate solution and boiled for 4 hours, and the turbid liquid was decanted, if repeating for 3 times, zeolite modification was completed, and then placed in an adsorption device after drying.

The lithium-rich liquid was passed through an adsorption column packed with a sodium-modified zeolite adsorbent at a rate of 5 times the adsorbent volume/hour at room temperature of 15c, and adsorption was completed after 2 hours.

Through detection, the concentration of lithium ions in the adsorbed low-sodium lithium-rich liquid is 9.7g/L, and the concentration of sodium ions is 4g/L.

Example 5

Preparation of sodium modified zeolite: taking 40g of natural square zeolite, grinding to 30-40 meshes, placing in 800ml of saturated sodium sulfate solution, boiling for 2 hours, pouring out turbid liquid, repeating for 6 times, finishing zeolite modification, drying and placing in an adsorption device.

After the lithium-rich liquid was warmed to 45 ℃, it was passed through an adsorption column containing a sodium-modified zeolite adsorbent at a flow rate of 1 time the adsorbent volume/hour, and adsorption was completed after 5 hours.

Through detection, the concentration of lithium ions in the adsorbed low-sodium lithium-rich liquid is 9.8g/L, and the concentration of sodium ions is 3.3g/L.

Example 6

Preparation of sodium modified zeolite: taking 40g of natural square zeolite, grinding to 30-40 meshes, placing in 400ml of saturated sodium sulfate solution, boiling for 3 hours, pouring out turbid liquid, repeating for 4 times, finishing zeolite modification, drying and placing in an adsorption device.

After the lithium-rich solution was warmed to 50 ℃, it was passed through an adsorption column containing a sodium-modified zeolite adsorbent at a 3-fold adsorbent volume/hour flow rate, and after 4 hours adsorption was completed.

Through detection, the concentration of lithium ions in the adsorbed low-sodium lithium-rich liquid is 10.0g/L, and the concentration of sodium ions is 3.4g/L.

Example 7

Preparation of sodium modified zeolite: taking 40g of natural square zeolite, grinding to 30-40 meshes, placing in 200ml of saturated sodium sulfate solution, boiling for 3 hours, pouring out turbid liquid, repeating for 5 times, finishing zeolite modification, drying and placing in an adsorption device.

As shown in fig. 7, the detailed operation method for reducing the concentration of sodium ions in the lithium-rich liquid is as follows: after the lithium-rich solution was warmed to 50 ℃, it was passed through an adsorption column containing a sodium-modified zeolite adsorbent at a flow rate of 2 times the adsorbent volume/hour, and after 4 hours adsorption was completed. The concentration of lithium ions in the low-sodium lithium-rich liquid after adsorption is 9.9g/L, and the concentration of sodium ions is 3.5g/L. The lithium-rich liquid can be crystallized and precipitated by simple concentration.

The sodium zeolite after the adsorption can be directly resolved. After the solution (Li⁺2.032g/L、Na⁺2.520g/L、K⁺0.206g/L、Ca²⁺0.020g/L、Mg²⁺0.312g/L、pH＝1.5) is introduced into the adsorption tower, the solution is circularly analyzed at a flow rate of 5 times of the volume of the adsorbent per hour, and the analysis is completed within 1 hour. After zeolite analysis, the lithium ion sieve analysis liquid becomes zeolite analysis liquid, wherein the concentration of lithium ions is 1.3g/L, the concentration of sodium ions is 5.6g/L, and the pH value is 2.0. The effective point in the sodium modified zeolite is occupied by hydrogen ions and lithium ions, the effective point is exchanged with sodium ions in the subsequent adsorption, and the lithium ions enter the lithium-rich liquid of the next round to be utilized.

After the zeolite desorption solution is obtained, the zeolite desorption solution and the lithium ion sieve desorption solution are mixed at a ratio of 1:1, and then the sodium zeolite after the adsorption is completed can be desorbed again. After repeated use for 4 times, the concentration of sodium ions in the zeolite resolving liquid is 10.2g/L, the zeolite resolving liquid is simply concentrated to 30g/L of sodium ions, then the zeolite resolving liquid is frozen to-10 ℃, a large amount of sodium sulfate decahydrate crystals are separated out, and the sodium sulfate decahydrate solid and the solution which can be continuously used in the resolving step after being diluted can be obtained through centrifugal separation.

The sodium sulfate decahydrate can be used for producing a sulfuric acid solution with the concentration of 1mol/L and a sodium hydroxide solution with the concentration of 1mol/L by a bipolar membrane electrodialysis method, wherein the sulfuric acid solution can be used for desorbing a lithium ion sieve adsorbent, and the sodium hydroxide solution can be used for adjusting the pH value of a desorption solution of the lithium ion sieve after further concentration.

Example 8

As shown in fig. 7, the detailed operation method for reducing the concentration of sodium ions in the lithium-rich liquid is as follows:

after the lithium-rich solution was warmed to 50 ℃, it was passed through an adsorption column containing a sodium-modified zeolite adsorbent at a flow rate of 4 times the adsorbent volume/hour, and after 4 hours adsorption was completed. The concentration of lithium ions in the low-sodium lithium-rich liquid after adsorption is 9.8g/L, and the concentration of sodium ions is 3.4g/L. The lithium-rich liquid can be crystallized and precipitated by simple concentration.

The sodium zeolite after the adsorption can be directly resolved. After passing the solution through the adsorption column using a lithium ion sieve (same as in example 7), the solution was analyzed at a flow rate of 10 times the volume of the adsorbent per hour, and the analysis was completed for 0.5 hour. After zeolite analysis, the lithium ion sieve analysis liquid becomes zeolite analysis liquid, wherein the concentration of lithium ions is 1.5g/L, the concentration of sodium ions is 5.1g/L, and the pH value is 1.9. The effective point in the sodium modified zeolite is occupied by hydrogen ions and lithium ions, the effective point is exchanged with sodium ions in the subsequent adsorption, and the lithium ions enter the lithium-rich liquid of the next round to be utilized.

After the zeolite desorption solution is obtained, the zeolite desorption solution and the lithium ion sieve desorption solution are mixed at a ratio of 1:5, and then the sodium zeolite after the adsorption is completed can be desorbed again. After the zeolite is repeatedly utilized for 82 times, the concentration of sodium ions in the zeolite analysis solution is 10.1g/L, the zeolite analysis solution is simply concentrated to 40g/L of sodium ions, then the zeolite is frozen to-10 ℃, a large amount of sodium sulfate decahydrate crystals are separated out, and the sodium sulfate decahydrate solid and the solution which can be continuously used in the analysis step after being diluted can be obtained through centrifugal separation.

Example 9

Preparation of sodium modified zeolite: taking 40g of natural square zeolite, grinding to 30-40 meshes, placing in 200mL of saturated sodium sulfate solution, boiling for 3 hours, pouring out turbid liquid, repeating for 4 times, finishing zeolite modification, drying, and placing in an adsorption device.

After the lithium-rich liquid was warmed to 50 ℃, it was passed through an adsorption column containing a sodium-modified zeolite adsorbent at a rate of 3.5 times the adsorbent volume/hour flow rate, and adsorption was completed after 3.5 hours. The concentration of lithium ions in the low-sodium lithium-rich liquid after adsorption is 9.5g/L, and the concentration of sodium ions is 3.7g/L. The lithium-rich liquid can be crystallized and precipitated by simple concentration.

The sodium zeolite after the adsorption can be directly resolved. After passing the solution (same as in example 7) through the adsorption column, the solution was analyzed at a flow rate of 8 times the volume of the adsorbent per hour for 45 minutes. After zeolite analysis, the lithium ion sieve analysis liquid becomes zeolite analysis liquid, wherein the concentration of lithium ions is 1.4g/L, the concentration of sodium ions is 5.4g/L, and the pH value is 2.0. The effective point in the sodium modified zeolite is occupied by hydrogen ions and lithium ions, the effective point is exchanged with sodium ions in the subsequent adsorption, and the lithium ions enter the lithium-rich liquid of the next round to be utilized.

After the zeolite desorption solution is obtained, the zeolite desorption solution and the lithium ion sieve desorption solution are mixed at a ratio of 1:3, and then the sodium zeolite after the adsorption is completed can be desorbed again. After the zeolite is repeatedly utilized for 32 times, the concentration of sodium ions in the zeolite analysis solution is 9.9g/L, the zeolite analysis solution is simply concentrated to 35g/L of sodium ions, then the zeolite is frozen to-10 ℃, a large amount of sodium sulfate decahydrate crystals are separated out, and the sodium sulfate decahydrate solid and the solution which can be continuously used in the analysis step after being diluted can be obtained through centrifugal separation.

Comparative example 3

This comparative example differs from example 4 only in that the natural analcite has not been subjected to sodium modification treatment. The concentration of lithium ions in the adsorbed sodium-removing lithium-rich liquid is about 9.2g/L, and the concentration of sodium ions is 10.4g/L.

Comparative example 4

The only difference compared to example 4 is that the adsorption temperature is 0℃lower (no ice formation). The concentration of lithium ions in the adsorbed sodium-removing lithium-rich liquid is about 10g/L, and the concentration of sodium ions is 11.3g/L.

Comparative example 5

The difference compared to example 4 is only that the adsorption temperature is 80℃at ambient temperature. The concentration of lithium ions in the adsorbed sodium-removing lithium-rich liquid is about 9.5g/L, and the concentration of sodium ions is 10.8g/L.

Comparative example 6

The only difference compared to example 4 is that saturated sodium carbonate is used instead of saturated sodium sulfate. The concentration of lithium ions in the adsorbed sodium-removing lithium-rich liquid is about 8.2g/L, and the concentration of sodium ions is 8.9g/L.

Example 10

In this embodiment, the low-sodium lithium-rich solution treated in embodiment 4 is selected, subjected to high-pressure reverse osmosis treatment, concentrated to a lithium ion concentration of about 30g/L, evaporated and crystallized continuously, and centrifugally separated to obtain a solid, namely lithium hydroxide monohydrate crystal, which can be dissolved in water and recrystallized to obtain a battery-grade lithium hydroxide product if the quality of lithium hydroxide monohydrate is further improved.

Example 11

In this embodiment, the low-sodium lithium-rich solution treated in embodiment 5 is selected, subjected to high-pressure reverse osmosis treatment, concentrated to a lithium ion concentration of about 30g/L, evaporated and crystallized continuously, and centrifugally separated to obtain a solid, namely lithium hydroxide monohydrate crystal, which can be dissolved in water and recrystallized to obtain a battery-grade lithium hydroxide product if the quality of lithium hydroxide monohydrate is further improved.

Example 12

In this example, the low-sodium lithium-rich solution treated in example 6 is selected, subjected to high-pressure reverse osmosis treatment, the solution is concentrated to a lithium ion concentration of about 30g/L, the concentrated solution is continuously evaporated and crystallized, and the obtained solid is lithium hydroxide monohydrate crystal through centrifugal separation, and if the quality of lithium hydroxide monohydrate is required to be further improved, the lithium hydroxide monohydrate crystal can be dissolved in water and then recrystallized, so that a battery-grade lithium hydroxide product is obtained.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.

Claims

1. The method for preparing lithium hydroxide by using the lithium-rich liquid obtained by the lithium ion sieve adsorption method is characterized by comprising the following steps:

The multilayer adsorption tower at least comprises:

the first water permeable structure is arranged in the tower cavity and positioned between two layers of the adsorption dishes which are vertically adjacent, and is provided with a water permeable state allowing water to pass through and a water isolation state limiting the water to pass through;

(2) Adjusting the pH value of the sulfate-enriched solution to 11-12.5 by adding sodium hydroxide, collecting a liquid part through solid-liquid separation to obtain a lithium-enriched solution, and respectively carrying out boron removal, calcium removal, magnesium removal and manganese removal on the lithium-enriched solution;

the sodium modified zeolite adsorbent is prepared by taking analcite as a raw material and carrying out modification treatment on saturated sodium sulfate;

Said modification treatment of said sodium modified zeolite adsorbent is to boil analcite in saturated sodium sulfate solution for 2-4 hours;

The temperature of the sodium ion adsorption treatment step is 10-60 ℃;

2. The method for preparing lithium hydroxide according to claim 1, wherein in the step (2), the pH of the enriched sulfate solution is adjusted to 12.0 by adding sodium hydroxide.

3. The method for preparing lithium hydroxide according to claim 1, wherein in the step (4), the solution obtained by solid-liquid separation is partially added to the lithium-rich solution and mixed.

4. The method for preparing lithium hydroxide by using a lithium-rich liquid obtained by a lithium ion sieve adsorption method according to claim 3, wherein in the step (4), the step of recrystallizing the lithium hydroxide monohydrate crystal is further included to obtain a battery-grade lithium hydroxide product.

5. The method for preparing lithium hydroxide according to any of claims 1-4, wherein the multi-layered adsorption tower comprises:

the first water permeable structure comprises a first partition plate and a second partition plate which are arranged in a stacked mode, and a plurality of water permeable holes are formed in the plate surfaces of the first partition plate and the second partition plate;

The first partition plate can rotate around the axis of the first partition plate so that the water permeable holes on the first partition plate and the water permeable holes on the second partition plate are mutually overlapped or mutually staggered.

6. The method for preparing lithium hydroxide by using a lithium ion sieve adsorption process according to claim 5, wherein in the multi-layer adsorption tower, the first separator and the second separator are both disposed obliquely to a horizontal plane, so that a liquid level lowest point and a liquid level highest point are formed between two adjacent first permeable structures.

7. The method for preparing lithium hydroxide by using a lithium-rich liquid obtained by an adsorption method of a lithium ion sieve according to claim 6, wherein in the multi-layer adsorption tower, a liquid inlet and a liquid outlet are arranged at the lowest point of each liquid level, and a liquid outlet is arranged at the highest point of each liquid level.

8. The method for preparing lithium hydroxide by using a lithium-rich liquid obtained by an adsorption method of a lithium ion sieve according to claim 7, wherein in the multi-layer adsorption tower, the adsorption vessel has a columnar structure, a first filter screen is arranged on the top surface of the adsorption vessel, and a second filter screen is arranged on the bottom surface of the adsorption vessel.

9. The method for preparing lithium hydroxide by using the lithium-ion sieve adsorption method according to claim 8, wherein the multi-layered adsorption tower further comprises a second permeable structure, which is disposed on the bottom surface of the adsorption vessel and is located on a side of the second filter opposite to the first filter, and the second permeable structure has a permeable state allowing water to pass therethrough and a water blocking state limiting water to pass therethrough.

10. The method for preparing lithium hydroxide according to any of claims 1-4, wherein in step (3):

Repeating the modification treatment for 3-6 times, and pouring out turbid liquid after each modification treatment is finished;

The dosage ratio of the saturated sodium sulfate solution to the analcite is 3-20mL/g;

the particle size of the analcite is 30-40 meshes.

11. The method for preparing lithium hydroxide utilizing a lithium ion sieve adsorption process according to claim 10, wherein the sodium ion adsorption treating step comprises the step of contacting the lithium rich liquid with the sodium modified zeolite adsorbent at a flow rate of 1-5 adsorbent volumes/hour.

12. The method for preparing lithium hydroxide by using a lithium-rich liquid obtained by a lithium ion sieve adsorption method according to claim 11, wherein the time of the sodium ion adsorption treatment step is 2-5 hours.

13. The method for preparing lithium hydroxide according to claim 12, further comprising a step of subjecting the adsorbed sodium modified zeolite adsorbent to a desorption treatment.

14. The method for preparing lithium hydroxide by using a lithium-rich solution obtained by a lithium ion sieve adsorption process according to claim 13, wherein the resolving treatment is performed by using a solution containing 0.05-0.3mol/L lithium sulfate with a pH of 1.5-2.

15. The method for preparing lithium hydroxide by using a lithium-rich solution obtained by a lithium ion sieve adsorption method according to claim 14, wherein the desorption treatment is performed by using a lithium ion sieve desorption solution.

16. The method for preparing lithium hydroxide using a lithium enriched liquid according to claim 15, wherein the resolving step comprises a step of contacting the lithium ion sieve resolving liquid with the sodium modified zeolite adsorbent after adsorption at a flow rate of 5 to 10 times of the adsorbent volume/hour for a time of 0.5 to 1 hour.