System for extracting lithium from salt lake brine through capillary crystallization

Abstract

The invention discloses a system for extracting lithium from salt lake brine through capillary crystallization, and relates to the technical field of brine resource development and utilization, the system comprises multiple stages of brine pools, each stage of brine pool comprises a brine reaction pool, each stage of brine reaction pool is located in a set of heat preservation chambers, and a lithium extraction device and a control system are installed in each heat preservation chamber; the lithium extraction device comprises a plurality of groups of woven steel core ropes, the bottom ends of the woven steel core ropes are inserted below the brine liquid level of the brine reaction tank, and the woven steel core ropes comprise a plurality of groups of porous fiber bundles which have capillary action on a saline solution. Different salts are separated and extracted according to different capillary salt absorption effects of the hydrophilic porous fibers on different salts, and the technical problem that high-magnesium-lithium-ratio separation is difficult in brine separation is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of brine resource development and utilization, and particularly relates to a system for extracting lithium from salt lake brine through capillary crystallization. Background Art

[0002] Lithium is the lightest metal in the world. Due to its special properties, lithium and its compounds have a wide range of special uses and are known as "energy metals" and "metals that drive the world forward." Currently, the world is promoting dual carbon and new energy, and the policy has an urgent demand for lithium products, and the demand for lithium is growing year by year.

[0003] One of the main resources of lithium is salt lake brine with high lithium content. The process of extracting lithium from salt lake brine is to evaporate and concentrate the brine step by step through a series of solar evaporation ponds, separate the lithium salt or high-concentration brine, and then purify it by the factory to produce lithium salt. The energy source of the processing process is mainly solar energy, and it has the advantages of simple process and easy adjustment of production scale.

[0004] At present, the various methods of extracting lithium from brine have high requirements for brine, complex process flow, high reagent cost, high equipment specifications, high energy consumption and water resource consumption, and are still in the stage of industrial trial scale. For example, the precipitation method has strict requirements for brine and is only applicable to brine with a low magnesium-lithium ratio; the solvent extraction method has problems such as extraction agent dissolution and equipment corrosion; the calcination leaching method has a complex process, serious equipment corrosion, and high power consumption. Summary of the invention

[0005] In view of the problems mentioned in the background technology, the purpose of the present invention is to provide a capillary crystallization lithium extraction system from salt lake brine to solve the problems mentioned in the background technology.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] A capillary crystallization lithium extraction system from salt lake brine comprises a multi-stage brine pool, each stage of the brine pool comprises a brine reaction pool, each stage of the brine reaction pool is respectively located in a group of insulation chambers, a lithium extraction device and a control system are installed in the insulation chambers, the lithium extraction device comprises a plurality of groups of braided steel core ropes, the bottom end of the braided steel core rope is inserted under the brine liquid surface of the brine reaction pool, and the braided steel core rope comprises a plurality of groups of porous fiber bundles having capillary action on the salt solution.

[0008] As a preferred technical solution, the braided steel core rope also includes a steel wire rope core, and a plurality of groups of porous fiber bundles are wrapped around and covered the steel wire rope core.

[0009] As a preferred technical solution, a rubber layer is provided on the outer wall of the steel wire rope core.

[0010] As an optimal technical solution, brine mixing equipment is installed at the bottom or slope around the brine reaction tank, a heat exchange module is installed on the inner wall of the brine reaction tank, a square grid net is detachably installed above the liquid surface of the brine reaction tank, and the brine reaction tank is installed in an insulation room.

[0011] As a preferred technical solution, the lithium extraction device also includes a grid frame, and the rope ends of the braided steel core rope are detachably mounted on the grid frame through rope end locking devices.

[0012] As a preferred technical solution, the lithium extraction device also includes a lifting and moving device, and the grid frame is installed on the output end of the lifting and moving device.

[0013] As a preferred technical solution, the insulation chamber includes an insulation chamber main body, the brine reaction tank is installed in the insulation chamber main body, a cold and warm air circulation device is installed on the insulation chamber main body, the cold and warm air circulation device is installed on both sides of the brine reaction tank, and a thermostatic window for assisting in regulating the temperature is installed above the roof or side wall of the insulation chamber main body.

[0014] As an optimal technical solution, the main body of the insulation chamber is connected to a vacuum pumping device, the output end of the vacuum pumping device is connected to a water vapor condenser, and the water vapor condenser is connected to a distilled water storage tank; one side of the water vapor condenser is connected to the inlet of the first-stage brine pool to preheat the brine entering the first-stage brine pool, and the other side is connected to the exhaust outlet of the main body of the insulation chamber and the inlet of the distilled water storage tank.

[0015] As a preferred technical solution, the control system includes a control panel. The brine reaction tank is equipped with a temperature sensor, a humidity sensor, a liquid level sensor, a density sensor, and an evaporation sensor, and all sensors are electrically connected to the control panel. The brine reaction tank is also equipped with a height recognition device or a weight recognition device with a reminder alarm function.

[0016] Beneficial Effects

[0017] The present invention is applied to the separation and extraction process of lithium, sodium, potassium, calcium, magnesium and other resources in brine according to the different capillary absorption effects of hydrophilic porous fibers on different salts, the phase diagram of water-salt system, cold and hot air circulation, and heat exchange of brine in the pool body. It not only solves the technical problem of separation of high magnesium-lithium ratio in brine separation, but also compared with the traditional large-scale salt field crystallization salt separation method, it innovatively applies the capillary absorption effect of hydrophilic porous fiber materials, cold and warm air circulation, and the phase diagram of water-salt system to the capillary action three-dimensional crystallization salt separation of brine, which greatly reduces the industrial footprint, simplifies and shortens the process flow, accelerates the lithium extraction efficiency and reduces the consumption of equipment and water resources. The equipment is easy to configure, install and transfer, and is easy to promote and apply.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural diagram of a capillary crystallization system for extracting lithium from salt lake brine proposed by the present invention;

[0020] Figure 2 This is the structural diagram of the insulation room and control system;

[0021] Figure 3 This is the structural diagram of the porous fiber braided steel core rope;

[0022] Figure 4 Schematic diagram of the porous fiber rope group and stainless steel grid frame structure.

[0023] Figure numerals: 101, first-level brine pool; 102, second-level brine pool; 103, third-level brine pool; 104, fourth-level brine pool; 1, brine reaction pool; 11, brine mixing equipment; 12, heat exchange module; 13, square grid mesh; 2, lithium extraction device; 21, braided steel core rope; 211, steel wire rope core; 212, porous fiber bundle; 22, rope head locking device; 23, lifting and moving device; 24, grid frame; 3, insulation room; 31, insulation room body; 32, cold and warm air circulation device; 33, temperature control window; 4, control system; 41, control panel; 42, temperature sensor; 43, humidity sensor; 44, liquid level sensor; 45, density sensor; 46, evaporation sensor; 47, height recognition device; 48, weight recognition device. DETAILED DESCRIPTION

[0024] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0025] Example 1

[0026] refer to Figures 1 to 4 The capillary crystallization lithium extraction system from salt lake brine described in this embodiment includes a multi-stage brine pool, preferably, includes four-stage brine pools, namely a primary brine pool 101, a secondary brine pool 102, a tertiary brine pool 103 and a quaternary brine pool 104, each brine pool is matched with a lithium extraction device 2, a heat preservation chamber 3 and a control system 4, and the lithium extraction device 2, the heat preservation chamber 3 and the control system 4 adjust data corresponding to different levels of the brine pool.

[0027] The different salts are obtained by gradual grading of brine pools.

[0028] Each level of brine pool includes a brine reaction pool 1. A brine mixing device 11 is installed at the bottom or slope around the brine reaction pool 1. A heat exchange module 12 is installed on the inner wall of the brine reaction pool 1. A square grid net 13 is detachably installed to fully cover the liquid surface of the brine reaction pool 1. The brine reaction pool 1 is installed in an insulation chamber 3.

[0029] The brine reaction pool 1 is used to contain brine. During the extraction process, the setting of the brine mixing device 11 makes the temperature field and concentration field of the brine more uniform, and the water quality changes in the pool are almost consistent during the three-dimensional crystallization process; the heat exchange module 12 has a heating or cooling function, which is used to control the temperature of the brine body in the pool; the square grid net 13 is used to separate the fiber rope group of the lithium extraction device 2 to prevent entanglement.

[0030] Preferably, the depth of the brine reaction pool 1 is 1-3 m, which can meet the requirements of large-volume brine processing and mixing, and facilitate the crystallization and storage of salts at the bottom of the brine reaction pool 1 .

[0031] Furthermore, the depth of the brine reaction tank 1 is about 1.5-2m, which can not only meet the requirements of processing volume and process, but also ensure operation safety.

[0032] It is worth noting that the brine mixing equipment 11 has one or a combination of a stirring device and a water pumping and injection device, which is used to mechanically disturb or force convection circulation of the brine in the regulating tank. Preferably, the brine mixing equipment 11 includes multiple groups of submersible pumps, and the multiple groups of submersible pumps are dispersedly installed at the bottom around the brine reaction tank 1.

[0033] It is worth noting that the heat source of the heat exchange module 12 can be photovoltaic heat utilization, hot and cold air circulation or a heating device, etc.

[0034] It is worth noting that the brine reaction tank 1 is designed according to the process processing capacity, the tank body can be built on the ground or dug underground, and the process is controlled to prevent corrosion and leakage.

[0035] Preferably, the square grille 13 is made of stainless steel or hard plastic. The square grille 13 made of stainless steel or hard plastic can prevent workers from accidentally falling into the pool during operation, and the detachable design is convenient for later maintenance and pool cleaning.

[0036] The lithium extraction device 2 includes multiple groups of braided steel core ropes 21 and a grid frame 24. The rope ends of the braided steel core ropes 21 are detachably mounted on the grid frame 24 through rope end locking devices 22. The bottom ends of the braided steel core ropes 21 are inserted below the brine liquid level of the brine reaction tank 1.

[0037] The grid frame 24 is used to install and support multiple groups of braided steel core ropes 21. The rope end locking device 22 fixes the braided steel core ropes 21 on the grid frame 24. The braided steel core ropes 21 are used to precipitate salts. When the braided steel core ropes 21 are saturated, the rope end locking device 22 is unlocked and the braided steel core ropes 21 can be taken out from the grid frame 24.

[0038] Preferably, the length of the braided steel core rope 21 is 1.5-2.5 m, and the bottom end of the braided steel core rope 21 penetrates 0.1-0.5 m into the brine liquid surface.

[0039] The depth of the bottom of the ground rope below the liquid surface of the brine reaction tank 1 is adjusted according to the density and composition of the brine. The brine density is large and the brine pool process impurities are more, so the depth below the liquid surface of the brine reaction tank 1 is reduced to prevent the salt absorption rope from being excessively crystallized and broken over a long period of time and reduce the difficulty of process control.

[0040] The braided steel core rope 21 comprises a steel wire rope core 211 and a plurality of groups of porous fiber bundles 212, wherein the plurality of groups of porous fiber bundles 212 are wound around and cover the steel wire rope core 211 to prevent the porous fiber bundles 212 from breaking when the braided steel core rope 21 is subjected to a large pulling force.

[0041] Preferably, a rubber layer is provided on the outer wall of the steel wire rope core 211 to increase the flexibility and tensile strength of the braided steel core rope 21 .

[0042] It is worth noting that the porous fiber bundle 212 is made of one or a combination of cellulose acetate, polyamide, polyacrylonitrile, and polyethylene terephthalate, including blending and modification of these materials, or adding hydrophilic or hydrophobic modifiers for modification to meet the requirements of hydrophilic core, hydrophobic surface, and sufficient strength.

[0043] The porous fiber bundle 212 has a hydrophilic core and a hydrophobic surface. The salt solution moves upward using the capillary action of the porous fiber rope, similar to the process of trees absorbing water from the roots to the leaves. As the water on the braided steel core rope 21 continues to rise, the water on the rope surface continues to evaporate, thereby crystallizing and precipitating salts. Since lithium salts, sodium salts, potassium salts, calcium salts, magnesium salts, etc. have different physical properties and solubilities, they will crystallize at different positions of the braided steel core rope 21. Among them, salts with high concentration and low solubility, such as sodium salts, potassium salts, calcium salts, magnesium salts, etc., will crystallize at lower positions, and lithium salts with low concentration and high solubility will crystallize at the top of the braided steel core rope 21 after the braided steel core rope 21 is adsorbed and saturated, thereby realizing three-dimensional crystallization separation of different salt zones along the height direction of the braided steel core rope 21.

[0044] Preferably, the rope end locking device 22 is a wire rope buckle, and the rope end is fixed to the grid frame 24 through the rope end locking device 22. After the rope end locking device 22 is unlocked, the rope end is separated from the grid frame 24.

[0045] Preferably, it also includes a lifting and moving device 23, such as an electric hoist, and the grid frame 24 is installed on the output end of the lifting and moving device 23. The grid frame 24 can be fixed at a certain position and can also be driven by the lifting and moving device 23 to lift or translate.

[0046] The insulation chamber 3 includes an insulation chamber main body 31, the insulation chamber main body 31 has a built-in insulation board, the brine reaction pool 1 is installed in the insulation chamber main body 31, a cold and warm air circulation device 32 is installed on the insulation chamber main body 31, the cold and warm air circulation device 32 is installed on both sides of the brine reaction pool 1, and a temperature-adjustable window 33 for assisting in regulating the temperature is installed above the roof or side wall of the insulation chamber main body 31.

[0047] The insulation chamber body 31 is used to provide a controllable insulation environment for the brine reaction pool 1, the cold and warm air circulation device 32 is used to adjust the temperature in the insulation chamber body 31, and the temperature-adjusting window 33 assists in adjusting the temperature.

[0048] Preferably, the insulation chamber body 31 is connected with a vacuum device, the output end of the vacuum device is connected with a water vapor condenser, and the water vapor condenser is connected with a distilled water temporary storage tank; the vacuum device is connected to the exhaust port of the insulation chamber body 31 to extract water vapor from the insulation chamber 3, the output end of the vacuum device is connected to the inlet of the water vapor condenser pipe, the condensed liquid is connected to the distilled water temporary storage tank, and the raw brine entering the primary brine pool 101 goes through the water vapor process, and is heated by preheating and then connected to the primary brine pool 101; the vacuum device extracts water vapor, reduces the pressure on the liquid surface, and helps to accelerate the concentration of the liquid. The extracted water vapor is condensed to produce distilled water as a byproduct, which is suitable for remote areas lacking pure water.

[0049] The cold and warm air circulation device 32 includes at least one set of fan units installed oppositely on both sides of the brine reaction tank 1. The opposite fan units provide hot air circulation or cold air circulation to the braided steel core rope 21, and control the braided steel core rope 21 to have a salt absorption temperature of 20-60°C and a crystallization temperature of 5-20°C according to the brine composition.

[0050] The heat source of the cold and warm air circulation device 32 can be a heating device, photovoltaic heat utilization, hot air circulation or geothermal heat, etc., and the cold source can be compressor refrigeration. The cold source and the heat source can be connected in series with the heat exchange module 12 to save energy.

[0051] The control system 4 includes a control panel 41. A temperature sensor 42, a humidity sensor 43, a liquid level sensor 44, a density sensor 45, and an evaporation sensor 46 are installed on the brine reaction tank 1, and all sensors are electrically connected to the control panel 41. The brine reaction tank 1 is also installed with a height recognition device 47 or a weight recognition device 48 with a reminder alarm function.

[0052] Preferably, the control panel 41 is installed on the side wall of the insulation chamber body 31 .

[0053] According to the density, composition, different materials of the brine and the different capillary forces of the porous fiber bundle 212 on salt and the phase diagram of the water-salt system, the temperature, humidity, liquid level, brine density and evaporation amount displayed on the control panel 41 are used to adjust the cold and warm air circulation device 31 and the temperature-adjusting window, and strictly control the temperature, actual evaporation amount, circulating air volume and temperature of the insulation chamber 3 corresponding to each level of the braided steel core rope 21, so as to concentrate the brine and gradually precipitate salts in grades, reduce the impurity salt content and the magnesium-lithium ratio, and obtain qualified lithium chloride brine or lithium chloride crystalline salt.

[0054] The obtained lithium chloride salt solution can enter the refining and impurity removal process. According to product requirements, it includes one or a combination of chelating resin for calcium and magnesium removal, chelating resin for boron removal, nanofiltration for calcium and magnesium removal, and electrodialysis for boron removal to obtain lithium-rich mother liquor, or calcium salt or alkali is added for impurity removal, and lithium carbonate mixed salt is precipitated by carbonization precipitation method, and lithium carbonate is obtained after washing and drying.

[0055] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0056] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0057] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0059] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A system for extracting lithium from salt lake brine by capillary crystallization, comprising a plurality of brine pools, each of which comprises a brine reaction pool (1), characterized in that: Each level of the brine reaction pool (1) is located in a group of insulation chambers (3), and a lithium extraction device (2) and a control system (4) are installed in the insulation chambers (3). The lithium extraction device (2) includes a plurality of groups of braided steel core ropes (21), and the bottom ends of the braided steel core ropes (21) are inserted below the brine liquid level of the brine reaction pool (1). The braided steel core ropes (21) include a plurality of groups of porous fiber bundles (212) having a capillary effect on the salt solution.

2. The system for extracting lithium from salt lake brine by capillary crystallization according to claim 1, characterized in that: The braided steel core rope (21) further comprises a steel wire rope core (211), and a plurality of groups of porous fiber bundles (212) are wound around and cover the steel wire rope core (211).

3. The system for extracting lithium by capillary crystallization from salt lake brine according to claim 2, characterized in that: A rubber layer is arranged on the outer wall of the steel wire rope core (211).

4. The system for extracting lithium from salt lake brine by capillary crystallization according to claim 1, characterized in that: A brine mixing device (11) is installed at the bottom or the side slope of the brine reaction pool (1), a heat exchange module (12) is installed on the inner wall of the brine reaction pool (1), a square grid net (13) is detachably installed to fully cover the liquid surface of the brine reaction pool (1), and the brine reaction pool (1) is installed in an insulation chamber (3).

5. The system for extracting lithium from salt lake brine by capillary crystallization according to claim 1, characterized in that: The lithium extraction device (2) also includes a grid frame (24), and the rope ends of the braided steel core rope (21) are detachably mounted on the grid frame (24) via rope end locking devices (22).

6. The system for extracting lithium from salt lake brine by capillary crystallization according to claim 5, characterized in that: The lithium extraction device (2) also includes a lifting and moving device (23), and the grid frame (24) is installed on the output end of the lifting and moving device (23).

7. The system for extracting lithium from salt lake brine by capillary crystallization according to claim 1, characterized in that: The insulation chamber (3) comprises an insulation chamber main body (31), a brine reaction pool (1) is installed in the insulation chamber main body (31), a cold and warm air circulation device (32) is installed on the insulation chamber main body (31), the cold and warm air circulation device (32) is installed on both sides of the brine reaction pool (1), and a temperature-adjusting window (33) for assisting in adjusting the temperature is installed above the roof or side wall of the insulation chamber main body (31).

8. The system for extracting lithium from salt lake brine by capillary crystallization according to claim 7, characterized in that: The insulation chamber body (31) is connected to a vacuum pumping device, the output end of the vacuum pumping device is connected to a water vapor condenser, and the water vapor condenser is connected to a distilled water temporary storage tank; one side of the water vapor condenser is connected to the inlet of the first-stage brine pool to preheat the brine entering the first-stage brine pool, and the other side is connected to the exhaust port of the insulation chamber body (31) and the inlet of the distilled water temporary storage tank.

9. The system for extracting lithium from salt lake brine by capillary crystallization according to claim 1, characterized in that: The control system (4) comprises a control panel (41); a temperature sensor (42), a humidity sensor (43), a liquid level sensor (44), a density sensor (45), and an evaporation sensor (46) are installed on the brine reaction tank (1); and all sensors are electrically connected to the control panel (41); and a height recognition device (47) or a weight recognition device (48) having a warning alarm function is also installed on the brine reaction tank (1).

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