Carbonate type brine lithium salt separation system and separation method

Abstract

The invention provides a carbonate type brine lithium salt separation system and a separation method. The carbonate type brine lithium salt separation method comprises the following steps: pretreating raw brine A to obtain brine B; discharging the brine B into a crystallization evaporation chamber, and separating out sodium chloride and potassium chloride to obtain lithium-rich brine C; the lithium-rich brine C is discharged into a low-temperature crystallization evaporation chamber, sodium chloride, potassium chloride, mirabilite and glaserite are separated out, and lithium-rich brine D is obtained; the lithium-rich brine D is discharged into a crystallization evaporation chamber, sylvinite and a lithium-rich solid H are separated out, and lithium-rich brine E is obtained; separating out coarse boron ore, and carrying out solid-liquid separation when lithium salt is separated out, so as to obtain lithium-rich brine F; adding a sodium carbonate solution into the lithium-rich brine F to obtain industrial-grade lithium carbonate and lithium precipitation mother liquor G; and the lithium precipitation mother liquor G and the lithium-rich brine B enter a crystallization evaporation chamber together, and sodium chloride and potassium chloride are removed. According to the carbonate type brine lithium salt separation method, efficient concentration and enrichment of lithium can be achieved, the product purity is improved, and the product yield is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of brine resource development and utilization, and in particular to a carbonate brine lithium salt separation system and separation method. Background Art

[0002] In traditional technology, the initial enrichment of lithium mostly adopts isothermal evaporation method, which increases the concentration of lithium ions by evaporating brine. However, after the liquid phase reaches saturation, the precipitation of lithium ions in the solid phase is dispersed and difficult to control, resulting in low lithium extraction efficiency, which is not conducive to subsequent processing and utilization. The enrichment method in salt lakes is significantly limited by natural conditions, such as climate and sunshine, making the lithium enrichment process "dependent on the weather" and lacking industrial controllability and efficiency.

[0003] The existing methods for extracting lithium in carbonate salt lakes and lithium carbonate lithium mother liquor mainly include precipitation and adsorption. Although the precipitation method can achieve the initial extraction of lithium, its process is lengthy, overly dependent on local natural climatic conditions, with extremely low automation, and the precipitation of Li+ is often insufficient, resulting in a low yield of the final product. What's more, in the mother liquor after lithium carbonate precipitation, the concentration of Li+ is still high, resulting in a significant waste of lithium resources. Although the adsorption method can produce high-value products such as lithium hydroxide, impurity ions such as carbonate, sulfate, and boron remain in the desorption solution during the desorption process. If lithium is directly concentrated without effective treatment, lithium carbonate will precipitate, which not only pollutes the membrane separation system and reduces its effectiveness, but also makes it difficult to efficiently enrich lithium. In addition, the adsorption method is also limited in terms of product purity. The presence of impurity ions such as sulfate and boron reduces the purity of the final lithium product and affects the market competitiveness of the product.

[0004] Current lithium extraction technologies have significant deficiencies in efficiency, purity, and environmental adaptability. Although the isothermal evaporation method is simple, the lithium precipitation pattern limits its extraction efficiency; while the precipitation method and adsorption method have their own advantages, they have defects in automation, product yield, and purity. In particular, impurity ions such as carbonate, sulfate, and boron ions in carbonate salt lake brine constitute a direct obstacle to the concentration and enrichment of lithium, limiting the output of high-purity lithium products. Summary of the invention

[0005] The main purpose of the present invention is to provide a carbonate brine lithium salt separation system and separation method, which can achieve efficient concentration and enrichment of lithium, improve product purity and improve product yield.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a method for separating lithium salt from carbonate brine is provided, comprising: S1, pre-treating the original brine A, and then removing the suspended matter and calcium and magnesium to obtain brine B; S2, discharging the brine B into a crystallization evaporation chamber for evaporation concentration and capillary crystallization, and precipitating sodium chloride and potassium chloride from a hydrophilic porous fiber rope group and an evaporation pool body to obtain lithium-rich brine C; S3, discharging the lithium-rich brine C into a low-temperature crystallization evaporation chamber for low-temperature evaporation, freezing denitrification and capillary crystallization, and precipitating sodium chloride and potassium sulfate from the pool body, and sodium chloride, potassium chloride, sodium chloride and potassium sulfate from the fiber rope group to obtain lithium-rich brine D; S4, discharging the lithium-rich brine D into a lithium salt crystallization evaporation chamber for evaporation concentration and capillary crystallization, and precipitating sodium chloride, potassium chloride, sodium chloride and potassium sulfate from the fiber rope group to obtain lithium-rich brine D. Evaporation concentration and capillary crystallization, using the pool body to precipitate sylvite, and the fiber rope group to precipitate lithium-rich solid H, to obtain lithium-rich brine E; S5, when the borate concentration in the lithium-rich brine E reaches a predetermined value, it is introduced into a boron ore pool, and fresh water or original brine or industrial acid is added for mixed reaction to precipitate crude boron ore. When lithium salt begins to precipitate, solid-liquid separation is performed to obtain lithium-rich brine F after solid-liquid separation; S6, adding excess soda ash solution to the lithium-rich brine F, stirring evenly, precipitating and crystallizing at 80-100°C, washing and drying the obtained crystals to obtain finished industrial-grade lithium carbonate, and obtaining lithium precipitation mother liquor G; S7, the lithium precipitation mother liquor G and the purified brine B enter the S2 step together to remove sodium chloride and potassium chloride therein.

[0007] By applying the technical solution of the present invention, the method for separating lithium salt from carbonate brine closely combines the capillary effect of hydrophilic porous fibers on salt solution, the control of evaporation process by a crystallization evaporation chamber, and the control of crystallization speed and salt content, and makes full use of the large solubility difference characteristics of different salts (such as lithium salts, sodium salts, potassium salts, etc.), and utilizes multi-stage brine pools to gradually grade and crystallize sodium chloride, potassium chloride, mirabilite, glauber's salt, lithium chloride, lithium sulfate, etc. The lithium salt with high solubility is crystallized in the rear brine pool and the top of the rope end after the fiber ropes in different brine pools are saturated with adsorption. The enriched lithium can be further precipitated to produce industrial-grade lithium carbonate, realizing three-dimensional crystallization separation of different salt zones along the lateral and height directions of the fiber rope, simplifying and shortening the process flow, greatly reducing energy consumption and shortening the lithium extraction cycle. The equipment is easy to configure, install and transfer, and is extremely easy to promote and apply for industrial demonstration and large-scale production. It comprehensively utilizes various resources in carbonate salt lake brine, and no chemical agents are used in the process of separating and enriching lithium, achieving clean production as much as possible, thereby greatly improving the problem of lithium separation and enrichment in carbonate salt lake brine.

[0008] Furthermore, the lithium ion content in the original brine A is 0.05-20 g / L, the sodium ion content is 5-160 g / L, the magnesium ion content is 0.1-10 g / L, the boron ion content is 0.01-5 g / L, the carbonate ion content is 10-80 g / L, the chloride ion content is 15-154 g / L, the sulfate content is 5-20 g / L, and the pH is 8-11. By controlling and optimizing the content of these ions, efficient precipitation and recovery of other salts such as sodium chloride, potassium chloride, and mirabilite can be achieved, thereby improving the economic benefits of the entire brine treatment.

[0009] Furthermore, in step S1, the step of pre-treating the raw brine A includes: removing sediment or organic matter by at least one of grid filtration, natural sedimentation, chemical flocculation, sand filtration, activated carbon adsorption, and ultrafiltration; the step of removing suspended matter and calcium and magnesium is carried out by passing the pre-treated raw brine A through an ion exchange resin, wherein the ion exchange resin is a polystyrene resin modified by aminoacetate or aminophosphoric acid ester. The implementation of this series of pre-treatment measures significantly improves the cleanliness of the brine, reduces equipment blockage and chemical reaction byproducts in the subsequent process, thereby improving the lithium extraction efficiency and product purity.

[0010] Furthermore, the evaporation process in the carbonate brine lithium salt separation method is achieved by the following steps:

[0011] Obtain the density and composition of brine in each step;

[0012] According to the density and composition of the obtained brine, the actual evaporation amount, temperature, humidity and capillary crystallization length of the brine in the corresponding capillary crystallization chamber are adjusted;

[0013] Control different salts in different brines to crystallize in different evaporation and crystallization chambers and different areas and height positions of fiber rope groups;

[0014] Collect lithium salts and other salts separately.

[0015] This evaporation control strategy simplifies the process of traditional lithium extraction, reduces energy consumption, and improves the economy and environmental friendliness of the entire lithium extraction system.

[0016] Furthermore, the fiber rope group is prepared by the following method:

[0017] Select one or more combinations of cellulose acetate, polyamide, polyacrylonitrile, and polyethylene terephthalate;

[0018] The selected materials are blended and modified, or modified by adding a hydrophilic or hydrophobic modifier, wherein the hydrophilic contact angle of the hydrophilic porous fiber is in the range of 0-80°;

[0019] The modified material is used to make a hydrophilic porous fiber rope group.

[0020] Furthermore, the hydrophilic contact angle of the hydrophilic porous fiber is in the range of 20-60°.

[0021] By blending modification or adding hydrophilic modifiers, the fiber rope group obtains an excellent hydrophilic core, which enables the fiber rope to efficiently absorb salt from brine.

[0022] Furthermore, in steps S2 and S4, the temperature of the liquid brine is between 10.0°C and 40.0°C, and the capillary crystallization temperature is between 15.0°C and 35.0°C; in step S3, the temperature of the low-temperature evaporation liquid brine is between 4°C and 10°C, the temperature of the frozen denitrification liquid brine is between -8.0°C and -4.0°C, and the capillary crystallization temperature is between 10.0°C and 20.0°C. This precise temperature control ensures that the salts are precipitated in order according to their solubility and crystallization characteristics, reduces the entrainment loss of lithium salts under inappropriate conditions, and improves the purity and yield of lithium salts.

[0023] Furthermore, in step S5, the predetermined value of borate concentration is greater than or equal to 30 g / L, the volume ratio of lithium-rich brine E to fresh water or original brine is 50:100 to 300:100, and the industrial acid is hydrochloric acid or sulfuric acid, and the amount used is 1 to 1.1 times the theoretical calculated value of the industrial acid. The direct mixing of lithium-rich brine E with fresh water or original brine and the addition of industrial acid avoids additional chemical precipitation steps, simplifies the process flow, reduces the use and cost of chemical agents, and reduces the burden of wastewater treatment.

[0024] Furthermore, in step S6, the mass concentration of Li+ in the lithium-rich brine E is greater than 20-30 g / L, and the molar ratio of carbonate ions to lithium ions in the mixed solution is 1-1.2:2. The setting of this ratio ensures that lithium ions and carbonate ions react almost completely to generate lithium carbonate precipitation without excessive formation of other carbonate byproducts, thereby improving the precipitation efficiency and purity of lithium carbonate.

[0025] Furthermore, after step S7, the following steps are further included:

[0026] Dissolving and purifying lithium-rich solid H; or,

[0027] The lithium-rich solid H is added to step S6 to precipitate lithium.

[0028] By dissolving and purifying again or directly adding the lithium precipitation step, this part of the lithium salt can be fully recovered and converted into a higher purity lithium carbonate product, avoiding the waste of resources and improving the economic efficiency of the entire lithium extraction process.

[0029] According to another aspect of the present invention, a carbonate brine lithium salt separation system is provided, which is applied to the above-mentioned carbonate brine lithium salt separation method, and comprises a crystallization evaporation chamber, wherein the crystallization evaporation chamber comprises:

[0030] brine pools;

[0031] A lithium extraction device, including a hydrophilic porous fiber rope group, can be moved to different brine pools for crystallization and salt precipitation;

[0032] The evaporation and insulation chamber, the brine pool and the lithium extraction device are all located in the evaporation and insulation chamber, and the evaporation and insulation chamber is used to adjust the evaporation temperature and humidity;

[0033] The control system is used to control the salt precipitation parameters in the multi-stage brine pool and evaporation and insulation chamber.

[0034] The carbonate brine lithium salt separation system achieves efficient, clean and automated extraction of carbonate salt lake lithium resources through its unique design and control strategy, which not only significantly improves the purity and yield of lithium salts, but also effectively reduces energy consumption and environmental pollution.

[0035] Furthermore, the brine pool includes a primary brine pool, a secondary brine pool and a tertiary brine pool. Each brine pool is provided with a brine mixing device and a brine heating module. The lithium extraction device also includes a square grid net and a grid frame. The top of the hydrophilic porous fiber rope group is connected to the grid frame, and the bottom is connected to the square grid net. The suspension method of the hydrophilic porous fiber rope group enables the fiber rope to fully contact the brine, and utilizes the capillary action to improve the rising and evaporation efficiency of the brine. The design of the square grid net and the grid frame avoids the entanglement of the fiber rope in the pool, ensures the continuity and uniformity of the capillary crystallization of the fiber rope group, and improves the efficiency and purity of lithium salt precipitation.

[0036] Furthermore, the hydrophilic porous fiber rope group includes a plurality of parallel porous fiber ropes, the porous fiber rope includes a steel wire rope core, a porous fiber bundle and a multi-strand fiber winding bundle, the porous fiber bundle is braided and wound around the outer periphery of the steel wire rope core, the multi-strand fiber winding bundle is wound around the outer periphery of the porous fiber bundle, and the porous fiber bundle is wound and fixed. This structure not only increases the total surface area of ​​the fiber rope and improves the salt adsorption and crystallization capabilities, but also provides additional protection for the overall stability of the fiber rope group, prevents the fiber rope from loosening or falling off in the brine pool, and ensures the continuity and reliability of the capillary crystallization process.

[0037] Furthermore, the lithium extraction device also includes a lifting and moving device arranged on the top of the hydrophilic porous fiber rope group, and a rope head fixing and unlocking device is also arranged on the top of the hydrophilic porous fiber rope group. The hydrophilic porous fiber rope group is detachably connected to the lifting and moving device through the rope head fixing and unlocking device. The detachable connection characteristics of the fiber rope group make the maintenance and cleaning of the fiber rope more convenient. After the fiber rope group is saturated with adsorption and salt crust is precipitated, the rope head fixing and unlocking device can be used to safely remove it from the lifting and moving device, and the surface salt crust can be cleaned or the whole system can be cleaned, thereby ensuring the reusability of the fiber rope and the continuous operation of the lithium extraction system. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0039] Figure 1 It is a process flow chart of the method for separating lithium salt from carbonate brine according to an embodiment of the present invention;

[0040] Figure 2 It is a structural schematic diagram of a carbonate brine lithium salt separation system according to an embodiment of the present invention;

[0041] Figure 3 2 is a schematic structural diagram of an evaporation and insulation chamber of a carbonate-type brine lithium salt separation system according to an embodiment of the present invention;

[0042] Figure 4 is a schematic structural diagram of a porous fiber rope of a carbonate brine lithium salt separation system according to an embodiment of the present invention; and

[0043] Figure 5 It is a layout structure diagram of the hydrophilic porous fiber rope group of the carbonate brine lithium salt separation system according to an embodiment of the present invention.

[0044] The above drawings include the following reference numerals:

[0045] 1. Brine pool; 2. Lithium extraction device; 3. Evaporation and insulation chamber; 4. Control system; 101. Primary brine pool; 102. Secondary brine pool; 103. Tertiary brine pool; 11. Brine mixing equipment; 12. Brine heating module; 13. Square grid net; 21. Porous fiber rope; 22. Rope head fixing and unlocking device; 23. Lifting and moving device; 24. Grid frame; 31. Insulation chamber body; 32. Cold and warm air circulation device; 33. Temperature control window; 41. Control panel; 42. Temperature sensor; 43. Humidity sensor; 44. Liquid level sensor; 45. Density sensor; 46. Evaporation sensor; 47. Fiber rope crystal height identification device; 48. Fiber rope weight identification device; 211. Steel wire rope core; 212. Porous fiber bundle; 213. Multi-strand fiber winding bundle. DETAILED DESCRIPTION

[0046] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0047] See also Figures 1 to 5 As shown, according to an embodiment of the present invention, a method for separating lithium salt from carbonate brine comprises:

[0048] S1, pre-treating the original brine A, then removing the suspended matter and calcium and magnesium to obtain brine B;

[0049] S2, discharge brine B into the crystallization evaporation chamber for evaporation concentration and capillary crystallization, and the hydrophilic porous fiber rope group and the evaporation pool body precipitate sodium chloride and potassium chloride to obtain lithium-rich brine C;

[0050] S3, discharge the lithium-rich brine C into a low-temperature crystallization evaporation chamber for low-temperature evaporation, freezing denitrification and capillary crystallization, use the pool body to precipitate sodium chloride, potassium chloride, sodium chloride and potassium chloride to obtain lithium-rich brine D;

[0051] S4, discharge the lithium-rich brine D into the lithium salt crystallization evaporation chamber for evaporation concentration and capillary crystallization, use the pool body to precipitate sylvite, and use the fiber rope group to precipitate lithium-rich solid H to obtain lithium-rich brine E;

[0052] S5, when the borate concentration in the lithium-rich brine E reaches a predetermined value, a boron ore pool is introduced, fresh water or original brine or industrial acid is added for mixed reaction, crude boron ore is precipitated, and solid-liquid separation is performed when lithium salt begins to precipitate, and lithium-rich brine F is obtained after solid-liquid separation;

[0053] S6, adding an excess of soda ash solution to the lithium-rich brine F, stirring evenly, and precipitating and crystallizing at 80-100° C., washing and drying the obtained crystals to obtain finished industrial-grade lithium carbonate, and obtaining lithium precipitation mother liquor G;

[0054] S7, the lithium precipitation mother liquor G and the purified brine B enter the S2 step together to remove the mixed salts such as sodium chloride and potassium chloride therein.

[0055] By applying the technical scheme of the present invention, the method for separating lithium salt from carbonate brine closely combines the capillary effect of hydrophilic porous fiber on salt solution, the crystallization evaporation chamber to control the evaporation process and then control the crystallization speed and salt content, makes full use of the large solubility difference characteristics of different salts such as lithium salt, sodium salt, potassium salt, etc., and uses multi-stage brine pools to gradually grade and crystallize sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, etc. After the fiber ropes of different brine pools are saturated with adsorption, the lithium salt with high solubility is crystallized in the rear brine pool and the top of the rope end, and the enriched lithium can be further precipitated to produce industrial-grade lithium carbonate, and the fiber rope can be separated into three-dimensional crystals in different salt zones along the lateral direction and the height direction, which simplifies and shortens the process flow, greatly reduces energy consumption and shortens the lithium extraction cycle, and the equipment is easy to configure, install and transfer, and is very easy to promote and apply, and conduct industrial demonstration and large-scale production; it comprehensively utilizes various resources in carbonate salt lake brine, and no chemical agents are used in the process of separating and enriching lithium, so as to achieve clean production as much as possible, thereby greatly improving the problem of lithium separation and enrichment in carbonate salt lake brine.

[0056] By pretreating the raw brine in step S1, suspended solids and impurity ions such as calcium and magnesium are effectively removed, providing purified brine B for the subsequent steps, laying the foundation for improving the efficiency and purity of lithium extraction. The capillary crystallization technology in steps S2 to S4 uses the capillary phenomenon of hydrophilic porous fiber ropes to achieve the sequential precipitation of different salts such as sodium chloride, potassium chloride, mirabilite, and glauberite at specific temperature, humidity, and evaporation, which not only improves the lithium enrichment efficiency, but also effectively reduces the content of impurity salts and improves the purity of the final product lithium carbonate. The multi-stage evaporation and capillary crystallization process in steps S2 to S4 avoids unnecessary energy waste by precisely controlling the temperature and humidity of each evaporation chamber, while accelerating the concentration rate of brine. The low-temperature evaporation and freezing denitrification technology in step S3 reduces the heat energy consumption in brine treatment. By controlling the temperature of the brine pool within a specific range, mirabilite and glauberite are efficiently precipitated, thereby reducing the energy consumption of the overall lithium extraction process. The byproducts such as sodium chloride, potassium chloride and mirabilite precipitated in the brine pool at different stages can be recycled and reused, which not only saves resources, but also reduces waste emissions and plays a positive role in environmental protection. The control system monitors and adjusts the evaporation, density, liquid level and component changes of brine in real time, as well as the temperature and humidity of capillary crystallization, realizing automatic control and improving the flexibility and efficiency of operation.

[0057] In step S5, by controlling the borate concentration and introducing the boron pool, the boron ions in the brine can be treated in a targeted manner, reducing their interference with lithium salt extraction, while recycling the precipitated crude boron ore, increasing the economic benefits of the entire process. By monitoring the borate concentration in the brine, the timing of introducing the boron pool can be accurately determined, ensuring the stability of the process and the purity of the lithium salt.

[0058] Step S6 uses precipitation method to prepare industrial-grade lithium carbonate, avoiding the complex process and excessive use of chemical agents in traditional lithium extraction methods, and reducing the risk of environmental pollution. Adding excess soda ash solution to lithium-rich brine E in step S6 means that the amount of sodium carbonate added to lithium-rich brine E exceeds the theoretical amount required for complete reaction with lithium ions. The purpose of this operation is to ensure that all lithium ions in the brine can react with carbonate ions CO3 2- Reaction to produce lithium carbonate precipitate Li2CO3. Excess soda solution can more effectively drive the reaction in the direction of producing lithium carbonate precipitation, and can also help precipitate other metal ions that may react with carbonate ions, such as calcium ions Ca 2+ and magnesium ion Mg 2+ , thereby further purifying the brine and improving the purity of the final product, lithium carbonate.

[0059] In step S5, the lithium precipitation mother liquor G is combined with the purified brine B through step S7 and enters the lithium salt crystallization evaporation chamber again, which improves the lithium recovery rate, reduces the raw material loss, and optimizes the cost-effectiveness of the entire process.

[0060] When the hydrophilic porous fiber rope group in steps S2 and S3 is saturated with lithium chloride or lithium sulfate salt shell, it is the trigger condition for the brine to be transferred to the lower evaporation crystallization chamber. The corresponding brine pool needs to be removed to allow the lithium salt to precipitate out of the hydrophilic porous fiber rope group in step S4 as much as possible. The corresponding salt can be collected manually or mechanically; after removing the salt shell, it can be put back into the corresponding brine pool for use.

[0061] In each step, by precisely controlling and rationally utilizing the physical and chemical properties of brine, the dependence on expensive chemicals is reduced and the production cost is lowered.

[0062] In one embodiment, the lithium ion content of the original halide A is 0.05-20 g / L, the sodium ion content is 5-160 g / L, the magnesium ion content is 0.1-10 g / L, the boron ion content is 0.01-5 g / L, the carbonate ion content is 10-80 g / L, the chloride ion content is 15-154 g / L, the sulfate content is 5-20 g / L, and the pH is 8-11.

[0063] By limiting the components of the original brine A, the common lithium ion concentrations in salt lake brine are covered, allowing the system to process brine from low concentration to high concentration, thereby improving the overall recovery rate of lithium resources. By clarifying the content range of each impurity ion in subsequent steps, the system can be designed and optimized more specifically to effectively remove these impurities and improve the purity of lithium salts. An alkaline environment is conducive to the stability of lithium ions and the precipitation of lithium carbonate. The optimization of pH value can promote the efficient precipitation of lithium carbonate while inhibiting other undesirable chemical reactions, such as the precipitation of magnesium and calcium hydroxides, thereby improving the efficiency of lithium extraction.

[0064] The content of carbonate, chloride and sulfate in brine has a direct impact on the selection and efficiency of lithium extraction process. By controlling and optimizing the content of these ions, other salts such as sodium chloride, potassium chloride, and mirabilite can be efficiently precipitated and recovered, thereby improving the economic benefits of the entire brine treatment.

[0065] The composition characteristics of the original halide A determine the setting of equipment parameters in the subsequent lithium extraction process. A reasonable composition range enables the graded crystallization of salts and the enrichment of lithium by precisely adjusting the temperature, humidity and evaporation amount at each stage, thereby reducing energy consumption and increasing the rate of lithium extraction. Limiting the range of lithium ions, impurity ions, pH values ​​and other key parameters in the original halide A can significantly improve the efficiency and purity of the lithium extraction process, achieve comprehensive recycling of resources, reduce energy consumption and the use of chemicals, improve system stability and operational flexibility, and also play a positive role in environmental protection and clean production.

[0066] The crystallization evaporation chamber in steps S2 to S4 is a capillary crystallization lithium extraction device manufactured by utilizing the different adsorption forces of hydrophilic fibers on salts and the phase diagram principle of the water-salt system. It has two functions of evaporation concentration and capillary crystallization. According to the density and composition of carbonate brine, the actual evaporation amount, temperature, humidity, capillary crystallization salt precipitation length of the brine in the capillary crystallization chamber are adjusted, and different salts in the brine are controlled to crystallize and precipitate salts in different crystallization chambers and different areas and height positions of the fiber rope group in turn, so as to collect lithium salts and other salts separately.

[0067] The porous fiber rope of the hydrophilic porous fiber rope group in steps S2 to S4 has a hydrophilic core and a hydrophobic surface property, and the fiber material is required to have sufficient capillary action and strength for the salt water; the salt solution moves upward by the capillary action of the porous fiber rope, similar to the process of trees absorbing water from the roots to the leaves upward, and as the water on the fiber rope continues to rise, the water on the rope surface continues to evaporate, thereby crystallizing and precipitating salt; since lithium salts, sodium salts, potassium salts, etc. have different physical properties and solubilities, they will crystallize at different positions of the fiber rope, among which salts with high concentration and low solubility (such as sodium salts, potassium salts, etc.) will crystallize at a lower position first, and lithium salts with high solubility will crystallize at the top of the bundle group after the fiber rope is saturated with adsorption, so as to realize three-dimensional crystallization separation of different salt zones in the height direction of the fiber rope; according to the density of the brine and the phase diagram of the water-salt system, the temperature and actual evaporation amount of the crystallization chamber of each level of the three-dimensional fiber rope group are strictly controlled, the brine is concentrated and the salts are gradually precipitated in stages, the impurity salt content is reduced, and qualified lithium-rich brine or lithium salt is obtained.

[0068] In one embodiment, in step S1, the step of pretreating the raw halide A includes: removing silt or organic matter by at least one of grid filtration, natural sedimentation, chemical flocculation, sand filtration, activated carbon adsorption, and ultrafiltration; the step of removing suspended matter and calcium and magnesium is carried out by passing the pretreated raw halide A through an ion exchange resin, wherein the ion exchange resin is a polystyrene resin modified by aminoacetate or aminophosphate.

[0069] The implementation of this series of pretreatment measures significantly improved the cleanliness of the brine, reduced equipment blockage and chemical reaction byproducts in the subsequent process, and thus improved the lithium extraction efficiency and product purity. The use of polystyrene resin modified with aminoacetate or aminophosphoester as an ion exchange resin has excellent removal capabilities for calcium and magnesium ions commonly found in carbonate salt lake brines, and can reduce the concentration of calcium and magnesium in the brine to an extremely low level, creating a purer environment for subsequent capillary crystallization lithium extraction. Through these pretreatment steps, not only is the stable operation of the lithium extraction system guaranteed, maintenance costs are reduced, but the physical and chemical properties of the brine are also optimized, ensuring the high efficiency of the lithium extraction process and the high-quality output of lithium salts.

[0070] In one embodiment, the evaporation process in the method for separating lithium salt from carbonate brine is achieved by the following steps:

[0071] Obtain the density and composition of brine in each step;

[0072] According to the density and composition of the obtained brine, the actual evaporation amount, temperature, humidity and capillary crystallization length of the brine in the corresponding capillary crystallization chamber are adjusted;

[0073] Control different salts in different brines to crystallize in different evaporation and crystallization chambers and different areas and height positions of fiber rope groups;

[0074] Collect lithium salts and other salts separately.

[0075] The evaporation process in the method for separating lithium salts from carbonate-type brine achieves efficient and selective separation of various salts in brine by precisely controlling and adjusting the environmental conditions of the brine in the capillary crystallization chamber, including the density, composition, actual evaporation amount, temperature, humidity and capillary crystallization length of the brine. This fine adjustment mechanism, based on a deep understanding of the characteristics of each brine, ensures that the salts are crystallized and precipitated in specific areas and heights according to their solubility and crystallization characteristics, among which sodium salts and potassium salts with low solubility and high concentrations are preferentially crystallized at lower positions, while lithium salts with high solubility are crystallized at the top area of ​​the fiber rope group to form a high-purity lithium salt shell. By gradually concentrating the brine in a multi-stage capillary crystallization evaporation chamber and controlling the precipitation order of the salts, not only the yield and purity of the lithium salt are greatly improved, but also the graded recovery of other salt resources in the brine, such as sodium chloride, potassium chloride, mirabilite, potassium mirabilite, etc., is achieved, reducing resource waste and environmental pollution. This innovative evaporation control strategy simplifies the process of traditional lithium extraction, reduces energy consumption, improves the economy and environmental friendliness of the entire lithium extraction system, and provides strong technical support for the efficient and green development of lithium resources.

[0076] In one embodiment, the fiber rope group is prepared by the following method:

[0077] Select one or more combinations of cellulose acetate, polyamide, polyacrylonitrile, and polyethylene terephthalate;

[0078] Blending and modifying the selected materials, or adding hydrophilic or hydrophobic modifiers for modification;

[0079] The modified material is used to make a hydrophilic porous fiber rope group.

[0080] The hydrophilic porous fiber has different hydrophilicities to different dissolved salts. To achieve the purpose of separation, the hydrophilic contact angle of the hydrophilic porous fiber is in the range of 0-80°. In one embodiment, the hydrophilic contact angle of the hydrophilic porous fiber is in the range of 20-60°.

[0081] By blending modification or adding hydrophilic modifiers, the fiber rope group obtains an excellent hydrophilic core, which enables the fiber rope to efficiently absorb salt from brine, especially lithium salt. The capillary action of the fiber rope is similar to the absorption of water by tree roots, but more precise. It can form three-dimensional crystal separation of different salts on the fiber rope according to the solubility characteristics of the salts, thereby significantly improving the separation efficiency and purity of lithium.

[0082] The hydrophobic surface properties of the fiber rope group ensure the directional movement and selective crystallization of the brine on the fiber rope. Salts with high concentration and low solubility, such as sodium salts and potassium salts, crystallize preferentially at the lower position of the fiber rope, while highly soluble lithium salts precipitate at the top area of ​​the fiber rope. This salt partitioning stereo crystallization separation technology effectively separates lithium from other salts in the brine, improving the yield and purity of lithium salts.

[0083] The selection and treatment of modified materials ensure the physical strength and chemical stability of the fiber rope group during the lithium extraction process from brine. The fiber rope can not only withstand the tension and shear force during the rising process of brine, but also maintain its structural and functional integrity during repeated use and cleaning, reducing the frequency of fiber rope replacement.

[0084] The modification of the fiber rope group improves its adaptability to different brine densities, components and environmental conditions. By adjusting the capillary force and crystallization conditions of the fiber rope group, the system can be flexibly adjusted according to the characteristics of specific brines, ensuring efficient extraction of lithium salts while reducing the complexity of the process and the difficulty of operation.

[0085] In one embodiment, in steps S2 and S4, the temperature of the liquid brine is between 10.0°C and 40.0°C, and the capillary crystallization temperature is between 15.0°C and 35.0°C; in step S3, the temperature of the low-temperature evaporation liquid brine is between 4°C and 10°C, the temperature of the frozen denitrification liquid brine is between -8.0°C and -4.0°C, and the capillary crystallization temperature is between 10.0°C and 20.0°C.

[0086] Different temperature ranges promote the crystallization of different salts in brine. At higher temperatures of 15.0°C to 35.0°C, sodium chloride and potassium chloride are precipitated first, while at lower temperatures of 10.0°C to 20.0°C, salts such as mirabilite and glauber's salt are easier to crystallize. This precise temperature control ensures that salts are precipitated in order according to their solubility and crystallization characteristics, reduces the entrainment loss of lithium salts under inappropriate conditions, and improves the purity and yield of lithium salts.

[0087] In step S4, by controlling the temperature in the lithium salt capillary crystallization evaporation chamber, it is beneficial to enrich the lithium salt relative to other salts. The setting of the liquid phase brine temperature and the capillary crystallization temperature accelerates the evaporation and concentration of the brine. At the same time, the capillary action of the fiber rope is used to precipitate the lithium salt in the top area of ​​the fiber rope, thereby achieving efficient separation and enrichment of the lithium salt and improving the quality of the final industrial-grade lithium carbonate.

[0088] Reasonable temperature control, especially the low-temperature evaporation and freezing denitrification process in step S3, reduces the energy required for brine evaporation and reduces the energy consumption of the entire lithium extraction system. At the same time, by controlling the evaporation rate of brine at different temperatures, the separation process of salts is accelerated, the efficiency of lithium extraction is improved, and the production cycle is shortened.

[0089] In one embodiment, in step S5, the predetermined value of the borate concentration is greater than or equal to 30 g / L, the volume ratio of the lithium-rich brine E to the fresh water or the original brine is 50:100 to 300:100, and the industrial acid is hydrochloric acid or sulfuric acid, and the amount used is 1 to 1.1 times the theoretical calculated value of the industrial acid.

[0090] When the borate concentration in the lithium-rich brine E reaches a preset threshold, the borate concentration can be effectively reduced by mixing with fresh water or original brine to avoid interference with the subsequent lithium extraction step. The addition of industrial acid further promotes the reaction and precipitation of borate, thereby precipitating crude boron ore, achieving the initial recovery of boron resources and purification of brine. In the process of removing borate, lithium salts are recovered in time through solid-liquid separation, avoiding the loss of lithium during the boron removal process. At the same time, the lithium-rich brine F after solid-liquid separation returns to step S4 to further concentrate the lithium salts in the brine, thereby improving the purity and yield of lithium.

[0091] The amount of industrial acid added is controlled at 1 to 1.1 times the theoretical calculated value. This slight excess design is conducive to promoting the chemical reaction in the reverse direction of lithium salt decomposition, reducing the formation of lithium carbonate in the brine, avoiding the contamination of membrane separation or adsorption materials by lithium carbonate, and creating conditions for the subsequent efficient separation of lithium. By adjusting the volume ratio of lithium-rich brine E to fresh water or original brine, not only can the removal efficiency of borate be controlled, but other salt resources in the brine, such as sodium chloride and potassium chloride, can also be further recovered and utilized, thereby improving the economic benefits of the entire lithium extraction process. The direct mixing of lithium-rich brine E with fresh water or original brine and the addition of industrial acid avoid additional chemical precipitation steps, simplify the process flow, reduce the use and cost of chemical agents, and reduce the burden of wastewater treatment, demonstrating the economy and environmental protection of the process design.

[0092] Step S5 performs solid-liquid separation on the lithium-rich brine, and the solid-liquid separation is a sedimentation separation, centrifugal separation, plate and frame filtration or membrane filtration separation operation.

[0093] The analysis of the components of the evaporation concentration and capillary crystallization salt precipitation in steps S2 to S4 can be carried out by phase identification and chemical analysis methods and means, including X-ray diffraction, Raman analysis, flame atomic absorption spectrophotometry, inductively coupled plasma spectrometry, etc.;

[0094] In steps S2 to S4, different sections of salt crusts on the fiber rope are collected. The salt crusts can be collected manually or mechanically in sections, or by using a horizontal rubber roller shelling device. The fiber rope group can be inverted as a whole in the height direction and enter the horizontal rubber roller for shelling. The bottom salt crust collection device can classify and collect the salt crusts according to different lengths.

[0095] The hydrophilic porous fiber rope group is placed in a horizontal rubber roller dehulling device in sections according to length. The fiber bundle group can be inverted as a whole in the height direction and enter the horizontal rubber roller for dehulling operation. The bottom salt shell collecting device can be changed according to different lengths.

[0096] The surface material of the rubber roller is rubber or silicone. The fiber bundles with crystallized salt on the surface fall off and enter the bottom collection tank or conveyor belt into different stirring tanks under the squeezing, impact and friction of the rubber rollers on both sides. The squeezing speed of the rubber roller can be controlled, and the shelling can be removed by slow squeezing to prevent damage to the fiber rope and improve the recovery rate of lithium salt.

[0097] In the method for separating lithium salt from carbonate brine, the temperature of the brine pool is raised to 10-40°C for high-temperature evaporation or 4-10°C for low-temperature evaporation. According to the density of the brine, the actual evaporation amount, the adsorption capacity of the fiber rope group to different salts and the phase diagram of the water-salt system, the evaporation amount is adjusted step by step so that most of the sodium and potassium in the salt lake brine are crystallized and precipitated as salts in the fiber rope group and the evaporation pool. Among the precipitated salts, less lithium is entrained, which can greatly improve the lithium yield.

[0098] In one embodiment, in step S6, the mass concentration of Li+ in the lithium-rich brine E is greater than 20-30 g / L, and the molar ratio of carbonate ions to lithium ions in the mixed solution is 1-1.2:2.

[0099] Adding soda ash solution to lithium-rich brine E promotes efficient precipitation of lithium carbonate by precisely controlling the ratio of carbonate ions to lithium ions. This ratio setting ensures that lithium ions and carbonate ions react almost completely to form lithium carbonate precipitation without excessive formation of other carbonate byproducts, thereby improving the precipitation efficiency and purity of lithium carbonate.

[0100] In one embodiment, step S7 further includes:

[0101] Dissolving and purifying lithium-rich solid H; or,

[0102] The lithium-rich solid H is added to step S6 to precipitate lithium.

[0103] The lithium-rich solid H is mainly composed of the lithium salt shell precipitated from the top of the fiber rope during the capillary crystallization process. This part of the lithium salt can be fully recovered and converted into a higher purity lithium carbonate product by re-dissolving and purifying or directly adding the lithium precipitation step, thus avoiding the waste of resources and improving the economic efficiency of the entire lithium extraction process.

[0104] See also Figures 2 to 5 As shown, according to an embodiment of the present invention, a carbonate brine lithium salt separation system is applied to the above-mentioned carbonate brine lithium salt separation method, including a crystallization evaporation chamber, and the crystallization evaporation chamber includes:

[0105] Brine pool 1;

[0106] The lithium extraction device 2 includes a hydrophilic porous fiber rope group, and the lithium extraction device 2 can be moved to different brine pools for crystallization and salt precipitation;

[0107] The evaporation and insulation chamber 3, the brine pool and the lithium extraction device 2 are all located in the evaporation and insulation chamber 3, and the evaporation and insulation chamber 3 is used to adjust the evaporation temperature and humidity;

[0108] The control system 4 is used to control the salt precipitation parameters in the multi-stage brine pool and the evaporation and insulation chamber 3.

[0109] The hydrophilic porous fiber rope group moves in different brine pools, combining the principle of the water-salt system phase diagram, and based on the density, composition and other characteristics of the brine, the salts in the brine are accurately classified according to solubility and crystallization characteristics, so that lithium salts and other salts can be collected separately, which significantly improves the purity and yield of lithium salts. The evaporation and insulation chamber can adjust the temperature and humidity of the evaporation process in the brine pool, ensuring that the capillary crystallization process is carried out under optimal conditions. This environmental control capability is crucial for the orderly precipitation of salts, avoiding interference from unstable factors such as temperature and humidity, and enhancing the stability and efficiency of the lithium extraction process.

[0110] The control system is responsible for monitoring and adjusting multiple parameters in the brine pool and evaporation and preservation chamber, including liquid level, temperature, humidity, density, evaporation, etc., to achieve automated control and intelligent management of the lithium extraction process. This system can respond quickly to real-time data and adjust process conditions in a timely manner, ensuring the continuity and efficiency of the lithium extraction process, while also reducing the complexity and cost of manual operations. The close cooperation between the brine pool, evaporation and preservation chamber, and lithium extraction device achieves efficient concentration of brine and recycling of salts.

[0111] The carbonate brine lithium salt separation system achieves efficient, clean and automated extraction of carbonate salt lake lithium resources through its unique design and control strategy, which not only significantly improves the purity and yield of lithium salts, but also effectively reduces energy consumption and environmental pollution.

[0112] The brine pool mainly provides the functions of mixing, storing, heat exchanging and zoning different brines; the porous fiber rope group lithium extraction device mainly provides the functions of lifting, moving, fixing and unlocking the porous hydrophilic fiber rope group. After the fiber rope group is saturated and the salt shell is precipitated, it is moved out of the brine pool or the fiber rope group to be adsorbed is hoisted into the designated area of ​​the brine pool; the evaporation and insulation chamber provides the main structure of the device and the industrial heating and cooling circulation device, and provides insulation, evaporation temperature and humidity adjustment and control; the control system provides the display of brine pool liquid level changes, temperature, humidity, density, evaporation amount and other information, and has functions such as reminder alarms, etc., which regulates and controls different salts in the brine to crystallize and precipitate salt in different crystallization chambers and different areas and height positions of the fiber rope group in turn.

[0113] In one embodiment, the brine pool 1 includes a primary brine pool 101, a secondary brine pool 102 and a tertiary brine pool 103, and each brine pool is provided with a brine mixing device 11 and a brine heating module 12. The lithium extraction device 2 also includes a square grid mesh 13 and a grid frame 24. The top end of the hydrophilic porous fiber rope group is connected to the grid frame 24, and the bottom end is connected to the square grid mesh 13.

[0114] Through the design of a multi-stage brine pool, the concentration of brine and the graded precipitation of salts can be gradually achieved. The brine mixing device 11 ensures the uniform distribution of brine in the pool, and the brine heating module 12 can adjust the temperature according to the brine composition and crystallization requirements, so that the brine pool can accurately control the evaporation rate and the precipitation order of salts, thereby improving the purity and yield of lithium salts.

[0115] The top of the hydrophilic porous fiber rope group is connected to the grid frame 24, and the bottom is connected to the square grid net 13. This suspension structure ensures the stability and mobility of the fiber rope group in the brine pool. The design of the grid frame and the square grid net not only provides support for the fiber rope group, but also facilitates the lifting and movement of the fiber rope group to adapt to the crystallization conditions in different brine pools, thereby enhancing the operational flexibility of the entire system.

[0116] The suspension method of the hydrophilic porous fiber rope group allows the fiber rope to fully contact the brine, using capillary action to improve the efficiency of brine rise and evaporation. The design of the square grid and grid frame avoids the entanglement of the fiber rope in the pool, ensures the continuity and uniformity of the capillary crystallization of the fiber rope group, and improves the efficiency and purity of lithium salt precipitation.

[0117] In one embodiment, the hydrophilic porous fiber rope group includes a plurality of porous fiber ropes 21 arranged in parallel, the porous fiber rope 21 includes a steel wire rope core 211, a porous fiber bundle 212 and a multi-strand fiber winding bundle 213, the porous fiber bundle 212 is woven and wound around the steel wire rope core 211, the multi-strand fiber winding bundle 213 is wound around the porous fiber bundle 212, and the porous fiber bundle 212 is wound and fixed.

[0118] The steel wire rope core 211 provides core support and reinforcement for the fiber rope, ensuring the mechanical strength and durability of the fiber rope during the lithium extraction process. The porous fiber bundle 212 is woven and wound around the outer periphery of the steel wire rope core. Its porous structure can provide a strong capillary effect, accelerating the rising speed of brine in the fiber, thereby improving the efficiency of evaporation and crystallization. The hydrophilic core of the porous fiber bundle can adsorb and carry salts in the brine, while the hydrophobic surface helps to reduce the adhesion of water, making it easier for the salt shell to crystallize. The multi-strand fiber winding bundle 213 is wound and fixed on the outer periphery of the porous fiber bundle 212. This structure not only increases the total surface area of ​​the fiber rope and improves the ability of salt adsorption and crystallization, but also provides additional protection for the overall stability of the fiber rope group, preventing the fiber rope from loosening or falling off in the brine pool, and ensuring the continuity and reliability of the capillary crystallization process.

[0119] In one embodiment, the lithium extraction device 2 also includes a lifting and moving device 23 arranged on the top of the hydrophilic porous fiber rope group, and a rope head fixing and unlocking device 22 is also arranged on the top of the hydrophilic porous fiber rope group. The hydrophilic porous fiber rope group is detachably connected to the lifting and moving device 23 through the rope head fixing and unlocking device 22.

[0120] The lifting and moving device 23 can accurately control the lifting and movement of the hydrophilic porous fiber rope group in different brine pools, ensuring that the fiber rope group can move to the optimal crystallization area according to the composition and temperature requirements of the brine, thereby improving the efficiency and purity of lithium salt precipitation. The rope head fixing and unlocking device 22 allows the fiber rope group to be detachably connected to the lifting and moving device 23. After the fiber rope group is saturated with adsorption, it can be quickly and easily removed and replaced with a new fiber rope group, which enhances the flexibility of operation, reduces downtime, and improves production efficiency.

[0121] The detachable connection feature of the fiber rope group makes the maintenance and cleaning of the fiber rope more convenient. After the fiber rope group is saturated with adsorption and the salt crust is precipitated, it can be safely removed from the lifting and moving device using the rope head fixing and unlocking device to clean the surface salt crust or the entire device, ensuring the reusability of the fiber rope and the continuous operation of the lithium extraction system.

[0122] In one embodiment, the evaporative insulation chamber 3 includes an insulation chamber main body 31, a cold and warm air circulation device 32, and a temperature-controlled window 33, and 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, an evaporation sensor 46, a fiber rope crystallization height identification device 47, and a fiber rope weight identification device 48.

[0123] The purified brine B is discharged into the primary brine pool 101, the secondary brine pool 102, and the tertiary brine pool 103 in sequence. A circulating pump is arranged outside the pool body for circulating operation, and a brine heating module 12 is used inside to adjust the temperature, and graded evaporation concentration and capillary crystallization salt precipitation are performed to control the evaporation amount, density, and liquid level of the brine to precipitate sodium chloride (NaCl), potassium chloride (KCl), sodium sulfate (Na2SO4·10H2O), potassium sulfate (K3NaSO4), lithium chloride (LiCl), lithium sulfate (Li2S04), etc. in sequence. After the density, liquid level, components, and retention time of the upper brine pool change, the brine is discharged into the lower brine pool or the next step in sequence. In steps S2 and S3, the hydrophilic porous fiber rope group saturates with lithium chloride or lithium sulfate salt shell, which is saturated and needs to be removed from the corresponding brine pool to allow the lithium salt to precipitate as much as possible in the capillary crystallization fiber rope group in step S4.

[0124] The porous fiber rope 21 above each brine pool 1 is arranged in a horizontal direction of 45 and a vertical direction of 55. The porous fiber rope 21 is fixed on the upper stainless steel grid frame 24 (horizontally 50 and vertically 60). The fiber material of the porous fiber rope 21 is modified cellulose acetate, lined with a stainless steel wire with a diameter of 0.8mm, and 5 modified cellulose acetate fiber bundles (end face diameter 0.6-1mm) are woven and wound on the wire. The outer surface of the wire is scratched to increase the bonding force between the fiber rope and the wire. The fiber rope is 1.5m long, and one end extends about 0.3m below the liquid surface; a stainless steel grid (horizontally 50 and vertically 60) is installed on the upper edge of the pool body to play a role in spacing and preventing entanglement, a liquid level sensor 44 and a temperature sensor 42 are installed inside the pool body, a humidity sensor 43, an evaporation sensor 46, a fiber rope crystal height identification device 47 and a fiber rope weight identification device 48 are installed in the room, and the brine density in the pool body is manually measured according to the density sensor 45. All data transmission is concentrated on a computer and recorded, displayed and controlled on the control panel 41.

[0125] The hot and cold air circulation device 32 includes a hot air circulation machine and a cold air circulation machine. The hot air circulation machine and the cold air circulation machine are industrial brand products on the market. Each brine pool is placed with 2-4 units (placed opposite each other) according to the brine composition and classification to control the evaporation of the water surface of the brine pool; there are 2 COB four-eye surface light lamps with a power of 200 watts above the brine pool. The light can be gathered and dispersed, and the irradiation angle can be adjusted to simulate the sunlight irradiation to each pool body, which is similar to the function of the temperature control window 33.

[0126] Compared with the existing lithium extraction technology, the present invention closely combines the capillary effect of hydrophilic porous fibers on salt solutions and the control of the evaporation process by industrial cooling and heating circulation fans to control the crystallization speed and salt content, fully utilizes the large solubility difference characteristics of different salts (such as lithium salts, sodium salts, potassium salts, etc.), and utilizes multi-stage brine pools to gradually grade and crystallize sodium chloride, potassium chloride, sodium sulfate, potassium glauber's salt, lithium chloride, lithium sulfate, etc. After the high-solubility lithium salt is adsorbed and saturated by the fiber ropes in different brine pools, it crystallizes in the rear brine pool and the top of the rope end. The enriched lithium can be further precipitated to produce industrial-grade lithium carbonate, and the fiber rope can be separated by three-dimensional crystallization in different salt zones in the lateral direction and the height direction, which simplifies and shortens the process flow, greatly reduces energy consumption and shortens the lithium extraction cycle. The equipment is easy to configure, install and transfer, and is very easy to promote and apply for industrial demonstration and large-scale production; it comprehensively utilizes various resources in carbonate salt lake brine, and no chemical agents are used in the process of separating and enriching lithium, so as to achieve clean production as much as possible; it fundamentally solves the problem of lithium separation and enrichment in carbonate salt lake brine.

[0127] For carbonate salt lake brine, the inventor innovatively combines the capillary effect of hydrophilic porous fibers on salt solutions, salt pan evaporation and concentration, and industrial hot and cold fans to control the evaporation process and thus the crystallization rate and salt content, making full use of the large solubility difference characteristics of different salts (such as lithium salts, sodium salts, potassium salts, etc.), and uses multi-stage brine pools to gradually grade and crystallize sodium chloride, potassium chloride and thenardite, potassium thenardite, lithium chloride, lithium sulfate, etc. Lithium salts and potassium salts with low solubility and high concentration first crystallize at a lower position, while lithium salts with high solubility are crystallized in the rear brine pool and the top of the rope end after the fiber ropes in different brine pools are saturated with adsorption, so as to achieve three-dimensional crystallization separation of different salt zones in the lateral direction and the height direction of the fiber rope, simplifying and shortening the process flow, greatly reducing energy consumption and shortening the lithium extraction cycle, and the equipment is easy to configure, install and transfer, and is very easy to promote and apply for industrial demonstration and large-scale production.

[0128] Implementation case 1:

[0129] The salt lake brine used in this embodiment is raw brine of a carbonate salt lake, wherein the concentration of lithium in the raw brine of the carbonate salt lake is 0.7 g / L, the concentration of carbonate is 30 g / L, the concentration of sulfate is 7 g / L, and the concentration of boron trioxide is 8 g / L.

[0130] S1. After the original brine A is filtered through a grid, naturally settled, and sand filtered, the silt and suspended matter in the brine are removed. The trace amount of calcium and magnesium in the brine is removed through a polystyrene ion exchange resin modified with aminoacetate to obtain a purified brine B, in which Mg 2+≤0.02ppm and Ca 2+≤0.02ppm. After the resin is saturated, it is regenerated into a hydrogen form using hydrochloric acid or sulfuric acid and then regenerated into a sodium form using sodium hydroxide;

[0131] S2, each time taking 600kg of purified brine B into the rock salt capillary crystallization evaporation chamber, placing it in the environmental simulation, adjusting the temperature of the evaporation pool to control the brine pool temperature at 25-30°C, controlling the capillary crystallization temperature of the fiber rope group at 25-35°C through the cold and hot fan exhaust and lighting equipment, monitoring the evaporation process, monitoring the Li+ concentration and K+ concentration in the brine, when the potassium chloride precipitated on the fiber rope group accounts for 85-90% of the salt crust component, stop this stage of capillary crystallization and high-temperature evaporation, obtain 39kg of solid salt ore (mainly sodium chloride, etc.), the fiber rope group precipitates 5kg of salt crust (mainly sodium chloride, potassium chloride), and obtain 100kg of lithium-rich brine C, the lithium content concentration reaches 4-4.5g / L;

[0132] S3, each time take 600kg lithium-rich brine C into the low-temperature capillary crystallization evaporation chamber, the brine pool low-temperature evaporation and freezing denitrification, placed in environmental simulation, adjust the temperature of the evaporation pool, the brine pool temperature is controlled at 4 ~ 10 ℃ low-temperature evaporation, the fiber rope group above the evaporation pool crystallization temperature is 10-15 ℃, the fiber rope group on the fiber rope group precipitation of mirabilite or potassium mirabilite accounted for 40 ~ 50% of the salt crust components, replace the new fiber rope group; control the brine pool temperature at -6 ~ -4 ℃, cool -0.5 ℃, place for 6 hours, Thenardite, potassium glauberite, etc. are precipitated in the evaporation pool, and the solid salt ore is discharged in time; the low-temperature evaporation, cooling and placement, and capillary crystallization process are repeated (1 to 2 times) until the lithium chloride and lithium sulfate precipitated on the fiber rope group account for 10 to 15% of the salt crust, and the capillary crystallization and low-temperature evaporation at this stage are stopped to obtain 10kg of solid salt ore (mainly thenardite, potassium glauberite, etc.), salt crust precipitated on the fiber rope group (mainly potassium chloride, thenardite, sodium chloride), and 185kg of lithium-rich brine D with a lithium content of 12 to 16g / L;

[0133] S4, each time taking 600kg lithium-rich brine D into the lithium salt capillary crystallization evaporation chamber, placing it in the environmental simulation, adjusting the temperature of the evaporation pool to control the brine pool temperature at 25-30°C, controlling the capillary crystallization temperature of the fiber rope group at 25-35°C by exhausting hot and cold fans, monitoring the evaporation process, monitoring the Li+ concentration in the brine, the fiber rope begins to precipitate lithium chloride salt shell (a small part of lithium sulfate) about 0.8m above the liquid surface, and replacing the saturated fiber rope group in time. When the Li+ concentration in the brine reaches 20-22g / L, stop this stage of capillary crystallization and evaporation, and obtain 2kg of solid salt ore (mainly potassium salt, a small part of lithium carbonate, etc.), the fiber rope group precipitates 4kg of salt shell (mainly lithium carbonate, lithium chloride, lithium-rich solid H), and obtains 390kg of lithium-rich brine E, the lithium content concentration reaches 25-30g / L, and the borate concentration reaches 30g / L at this time;

[0134] S5, when the borate concentration in the lithium-rich brine E reaches 30 g / L or more, the lithium-rich brine E is introduced into a boron ore pool, and fresh water is added for mixed reaction to precipitate crude boron ore, wherein the volume ratio of the boron-rich lithium brine E to fresh water is 150%; when lithium salt begins to precipitate, solid-liquid separation is performed, and 650 kg of lithium-rich brine F is obtained after solid-liquid separation, and the process returns to step S4 until the lithium content of the lithium-rich brine E reaches 20-22 g / L and the borate content is less than 10 g / L, and 440 kg of lithium-rich brine F is obtained;

[0135] S6. When the lithium content of the above 420kg lithium-rich brine F reaches 20-22g / L and the borate content is less than 10g / L, add an excess of soda ash solution, the amount of which is 1.2 times the theoretical value, stir evenly, and precipitate and crystallize at 80-100°C. The obtained crystals are washed and dried to obtain 40kg of finished industrial-grade lithium carbonate and 800kg of lithium precipitation mother liquor G. The lithium content of the lithium precipitation mother liquor reaches 2-4g / L.

[0136] S7, 800 kg of lithium precipitation mother liquor G is combined with purified brine B to enter step S2, and mixed salts such as sodium chloride and potassium chloride in the lithium precipitation mother liquor are removed to increase the concentration of lithium salt in the lithium-rich brine, thereby increasing the purity and length of the capillary crystallized lithium salt of the fiber rope group, and collecting the salt shell of the lithium salt at the top of the fiber rope group in step S4 to obtain lithium-rich solid H.

[0137] Industrial-grade lithium carbonate and lithium-rich solid H2 are combined, and the total yield of process lithium ions is calculated to be 75%.

[0138] Implementation case 2:

[0139] The salt lake brine used in this embodiment is raw brine of a carbonate salt lake, wherein the concentration of lithium in the raw brine of the carbonate salt lake is 0.7 g / L, the concentration of carbonate is 30 g / L, the concentration of sulfate is 7 g / L, and the concentration of boron trioxide is 8 g / L.

[0140] S1. After the original brine A is filtered through a grid, naturally settled, and sand filtered, the silt and suspended matter in the brine are removed. The trace amount of calcium and magnesium in the brine is removed through a polystyrene ion exchange resin modified with aminoacetate to obtain a purified brine B, in which Mg 2+≤0.02ppm and Ca 2+≤0.02ppm. After the resin is saturated, it is regenerated into a hydrogen form using hydrochloric acid or sulfuric acid and then regenerated into a sodium form using sodium hydroxide;

[0141] S2, each time taking 600kg of purified brine B into the rock salt capillary crystallization evaporation chamber, placing it in the environmental simulation, adjusting the temperature of the evaporation pool to control the brine pool temperature at 25-30°C, controlling the capillary crystallization temperature of the fiber rope group at 25-35°C through the cold and hot fan exhaust and lighting equipment, monitoring the evaporation process, monitoring the Li+ concentration and K+ concentration in the brine, when the potassium chloride precipitated on the fiber rope group accounts for 85-90% of the salt crust component, stop this stage of capillary crystallization and high-temperature evaporation, obtain 39kg of solid salt ore (mainly sodium chloride, etc.), the fiber rope group precipitates 5kg of salt crust (mainly sodium chloride, potassium chloride, etc.), and obtain 100kg of lithium-rich brine C, the lithium content concentration reaches 4-4.5g / L;

[0142] S3, each time take 600kg lithium-rich brine C into the low-temperature capillary crystallization evaporation chamber, the brine pool low-temperature evaporation and freezing denitrification, put it in the environmental simulation, adjust the temperature of the evaporation pool, the brine pool temperature is controlled at 4 ~ 10 ℃ low-temperature evaporation, the fiber rope group above the evaporation pool crystallization temperature is 10 ~ 15 ℃, the fiber rope group on the fiber rope group precipitation of mirabilite or potassium mirabilite accounted for 40 ~ 50% of the salt crust components, replace the new fiber rope group; control the temperature of the brine pool at -8 ~ -6 ℃, cool -0.5 ℃, place for 6 hours, steam Then, the saltpeter and potassium glauber's salt are precipitated from the pool, and the solid salt ore is discharged in time; the low-temperature evaporation, cooling and placement, and capillary crystallization process are repeated (1 to 2 times) until the lithium chloride and lithium sulfate precipitated on the fiber rope group account for 10 to 15% of the salt crust, and the capillary crystallization and low-temperature evaporation at this stage are stopped to obtain 11 kg of solid salt ore (mainly saltpeter and potassium glauber's salt, etc.), salt crust precipitated from the fiber rope group (mainly potassium chloride, saltpeter, sodium chloride, etc.), and 180 kg of lithium-rich brine D with a lithium content of 13 to 17 g / L;

[0143] S4, each time taking 600kg lithium-rich brine D into the lithium salt capillary crystallization evaporation chamber, placing it in the environmental simulation, adjusting the temperature of the evaporation pool to control the brine pool temperature at 25-30°C, controlling the capillary crystallization temperature of the fiber rope group at 25-35°C by exhausting hot and cold fans, monitoring the evaporation process, monitoring the Li+ concentration in the brine, the fiber rope begins to precipitate lithium chloride salt shell (a small part of lithium sulfate) about 0.8m above the liquid surface, and replacing the saturated fiber rope group in time. When the Li+ concentration in the brine reaches 20-22g / L, stop this stage of capillary crystallization and evaporation, and obtain 2kg of solid salt ore (mainly potassium salt, a small part of lithium carbonate, etc.), the fiber rope group precipitates 4kg of salt shell (mainly lithium carbonate, lithium chloride, lithium-rich solid H), and obtains 396kg of lithium-rich brine E, the lithium content concentration reaches 25-30g / L, and the borate concentration reaches 30g / L at this time;

[0144] S5, when the borate concentration in the lithium-rich brine E reaches 30 g / L or more, the lithium-rich brine E is introduced into a boron ore pool, and fresh water is added for mixed reaction to precipitate crude boron ore, wherein the volume ratio of the boron-rich lithium brine E to fresh water is 150%; when lithium salt begins to precipitate, solid-liquid separation is performed, and 660 kg of lithium-rich brine F is obtained after solid-liquid separation, and the process returns to step S4 until the lithium content of the lithium-rich brine E reaches 20-22 g / L and the borate content is less than 10 g / L, and 430 kg of lithium-rich brine F is obtained;

[0145] S6. When the lithium content of the above 430kg lithium-rich brine F reaches 20-22g / L and the borate content is less than 10g / L, add an excess of soda ash solution, the amount of which is 1.2 times the theoretical value, stir evenly, and precipitate and crystallize at 80-100°C. The obtained crystals are washed and dried to obtain 41.5kg of finished industrial-grade lithium carbonate and 800kg of lithium precipitation mother liquor G. The lithium content of the lithium precipitation mother liquor reaches 2-4g / L.

[0146] S7, 800 kg of lithium precipitation mother liquor G is combined with purified brine B to enter step S2, and mixed salts such as sodium chloride and potassium chloride in the lithium precipitation mother liquor are removed to increase the concentration of lithium salt in the lithium-rich brine, thereby increasing the purity and length of the capillary crystallized lithium salt of the fiber rope group, and collecting the salt shell of the lithium salt at the top of the fiber rope group in step S4 to obtain lithium-rich solid H.

[0147] Industrial-grade lithium carbonate and lithium-rich solid H2 were combined, and the total yield of process lithium ions was calculated to be 75.5%.

[0148] Implementation case three:

[0149] The salt lake brine used in this embodiment is raw brine of a carbonate salt lake, wherein the concentration of lithium in the raw brine of the carbonate salt lake is 0.7 g / L, the concentration of carbonate is 30 g / L, the concentration of sulfate is 7 g / L, and the concentration of boron trioxide is 8 g / L.

[0150] S1. After the original brine A is filtered through a grid, naturally settled, and sand filtered, the silt and suspended matter in the brine are removed. The trace amount of calcium and magnesium in the brine is removed through a polystyrene ion exchange resin modified with aminoacetate to obtain a purified brine B, in which Mg 2+≤0.02ppm and Ca 2+≤0.02ppm. After the resin is saturated, it is regenerated into a hydrogen form using hydrochloric acid or sulfuric acid and then regenerated into a sodium form using sodium hydroxide;

[0151] S2, each time taking 600kg of purified brine B into the rock salt capillary crystallization evaporation chamber, placing it in the environmental simulation, adjusting the temperature of the evaporation pool to control the brine pool temperature at 25-30°C, controlling the capillary crystallization temperature of the fiber rope group at 25-35°C through the cold and hot fan exhaust and lighting equipment, monitoring the evaporation process, monitoring the Li+ concentration and K+ concentration in the brine, when the potassium chloride precipitated on the fiber rope group accounts for 85-90% of the salt crust component, stop this stage of capillary crystallization and high-temperature evaporation, obtain 39kg of solid salt ore (mainly sodium chloride, etc.), the fiber rope group precipitates 5kg of salt crust (mainly sodium chloride, potassium chloride, etc.), and obtain 100kg of lithium-rich brine C, the lithium content concentration reaches 4-4.5g / L;

[0152] S3, each time take 600kg lithium-rich brine C into the low-temperature capillary crystallization evaporation chamber, the brine pool low-temperature evaporation and freezing denitrification, put it in the environmental simulation, adjust the temperature of the evaporation pool, the brine pool temperature is controlled at 4 ~ 10 ℃ low-temperature evaporation, the fiber rope group above the evaporation pool crystallization temperature is 10 ~ 15 ℃, the fiber rope group on the fiber rope group precipitation of mirabilite or potassium mirabilite accounted for 40 ~ 50% of the salt crust components, replace the new fiber rope group; control the temperature of the brine pool at -8 ~ -6 ℃, cool -0.5 ℃, place for 6 hours, steam Then, the saltpeter and potassium glauber's salt are precipitated from the pool, and the solid salt ore is discharged in time; the low-temperature evaporation, cooling and placement, and capillary crystallization process are repeated (1 to 2 times) until the lithium chloride and lithium sulfate precipitated on the fiber rope group account for 10 to 15% of the salt crust, and the capillary crystallization and low-temperature evaporation at this stage are stopped to obtain 11 kg of solid salt ore (mainly saltpeter and potassium glauber's salt, etc.), salt crust precipitated from the fiber rope group (mainly potassium chloride, saltpeter, sodium chloride, etc.), and 180 kg of lithium-rich brine D with a lithium content of 13 to 17 g / L;

[0153] S4, each time taking 600kg lithium-rich brine D into the lithium salt capillary crystallization evaporation chamber, placing it in the environmental simulation, adjusting the temperature of the evaporation pool to control the brine pool temperature at 25-30°C, controlling the capillary crystallization temperature of the fiber rope group at 25-35°C by exhausting hot and cold fans, monitoring the evaporation process, monitoring the Li+ concentration in the brine, the fiber rope begins to precipitate lithium chloride salt shell (a small part of lithium sulfate) about 0.8m above the liquid surface, and replacing the saturated fiber rope group in time. When the Li+ concentration in the brine reaches 20-22g / L, stop this stage of capillary crystallization and evaporation, and obtain 2kg of solid salt ore (mainly potassium salt, a small part of lithium carbonate, etc.), the fiber rope group precipitates 4kg of salt shell (mainly lithium carbonate, lithium chloride, lithium-rich solid H), and obtains 396kg of lithium-rich brine E, the lithium content concentration reaches 25-30g / L, and the borate concentration reaches 30g / L at this time;

[0154] S5. When the borate concentration in the lithium-rich brine E reaches 30 g / L or more, the lithium-rich brine E is introduced into a boron ore pool, and industrial hydrochloric acid is added for mixed reaction to precipitate crude boron ore. The amount used should be 1.1 times the theoretical calculated value. When lithium salt begins to precipitate, solid-liquid separation is performed. After solid-liquid separation, 620 kg of lithium-rich brine F is obtained, and the process returns to step S4 until the lithium content of the lithium-rich brine E reaches 23-25 ​​g / L and the borate content is less than 10 g / L, and 410 kg of lithium-rich brine F is obtained.

[0155] S6. When the lithium content of the above 410kg lithium-rich brine F reaches 23-25g / L and the borate content is less than 10g / L, add an excess of soda ash solution, the amount of which is 1.2 times the theoretical value, stir evenly, and precipitate and crystallize at 80-100°C. The obtained crystals are washed and dried to obtain 43kg of finished industrial-grade lithium carbonate and 800KG of lithium precipitation mother liquor G. The lithium content of the lithium precipitation mother liquor reaches 2-4g / L.

[0156] S7, 800 kg of lithium precipitation mother liquor G is combined with purified brine B to enter step S2, and mixed salts such as sodium chloride and potassium chloride in the lithium precipitation mother liquor are removed to increase the concentration of lithium salt in the lithium-rich brine, thereby increasing the purity and length of the capillary crystallized lithium salt of the fiber rope group, and collecting the salt shell of the lithium salt at the top of the fiber rope group in step S4 to obtain lithium-rich solid H.

[0157] Industrial-grade lithium carbonate and lithium-rich solid H2 are combined, and the total yield of process lithium ions is calculated to be 76%.

[0158] Implementation Case 4:

[0159] The salt lake brine used in this embodiment is raw brine of a carbonate salt lake, wherein the concentration of lithium in the raw brine of the carbonate salt lake is 0.7 g / L, the concentration of carbonate is 30 g / L, the concentration of sulfate is 7 g / L, and the concentration of boron trioxide is 8 g / L.

[0160] S1. After the original brine A is filtered through a grid, naturally settled, and sand filtered, the silt and suspended matter in the brine are removed. The trace amount of calcium and magnesium in the brine is removed through a polystyrene ion exchange resin modified with aminoacetate to obtain a purified brine B, in which Mg 2+≤0.02ppm and Ca 2+≤0.02ppm. After the resin is saturated, it is regenerated into a hydrogen form using hydrochloric acid or sulfuric acid and then regenerated into a sodium form using sodium hydroxide;

[0161] S2, each time taking 600kg of purified brine B into the rock salt capillary crystallization evaporation chamber, placing it in the environmental simulation, adjusting the temperature of the evaporation pool to control the brine pool temperature at 25-30°C, controlling the capillary crystallization temperature of the fiber rope group at 25-35°C through the cold and hot fan exhaust and lighting equipment, monitoring the evaporation process, monitoring the Li+ concentration and K+ concentration in the brine, when the potassium chloride precipitated on the fiber rope group accounts for 85-90% of the salt crust component, stop this stage of capillary crystallization and high-temperature evaporation, obtain 39kg of solid salt ore (mainly sodium chloride, etc.), the fiber rope group precipitates 5kg of salt crust (mainly sodium chloride, potassium chloride, etc.), and obtain 100kg of lithium-rich brine C, the lithium content concentration reaches 4-4.5g / L;

[0162] S3, each time take 600kg lithium-rich brine C into the low-temperature capillary crystallization evaporation chamber, the brine pool low-temperature evaporation and freezing denitrification, put it in the environmental simulation, adjust the temperature of the evaporation pool, the brine pool temperature is controlled at 4 ~ 10 ℃ low-temperature evaporation, the fiber rope group above the evaporation pool crystallization temperature is 10 ~ 15 ℃, the fiber rope group on the fiber rope group precipitation of mirabilite or potassium mirabilite accounted for 40 ~ 50% of the salt crust components, replace the new fiber rope group; control the temperature of the brine pool at -8 ~ -6 ℃, cool -0.5 ℃, place for 6 hours, steam Then, the saltpeter and potassium glauber's salt are precipitated from the pool, and the solid salt ore is discharged in time; the low-temperature evaporation, cooling and placement, and capillary crystallization process are repeated (1 to 2 times) until the lithium chloride and lithium sulfate precipitated on the fiber rope group account for 10 to 15% of the salt crust, and the capillary crystallization and low-temperature evaporation at this stage are stopped to obtain 11 kg of solid salt ore (mainly saltpeter and potassium glauber's salt, etc.), salt crust precipitated from the fiber rope group (mainly potassium chloride, saltpeter, sodium chloride, etc.), and 180 kg of lithium-rich brine D with a lithium content of 13 to 17 g / L;

[0163] S4, each time taking 600kg lithium-rich brine D into the lithium salt capillary crystallization evaporation chamber, placing it in the environmental simulation, adjusting the temperature of the evaporation pool to control the brine pool temperature at 25-30°C, controlling the capillary crystallization temperature of the fiber rope group at 25-35°C by exhausting hot and cold fans, monitoring the evaporation process, monitoring the Li+ concentration in the brine, the fiber rope begins to precipitate lithium chloride salt shell (a small part of lithium sulfate) about 0.8m above the liquid surface, and replacing the saturated fiber rope group in time. When the Li+ concentration in the brine reaches 20-22g / L, stop this stage of capillary crystallization and evaporation, and obtain 2kg of solid salt ore (mainly potassium salt, a small part of lithium carbonate, etc.), the fiber rope group precipitates 4kg of salt shell (mainly lithium carbonate, lithium chloride, lithium-rich solid H), and obtains 396kg of lithium-rich brine E, the lithium content concentration reaches 25-30g / L, and the borate concentration reaches 30g / L at this time;

[0164] S5. When the borate concentration in the lithium-rich brine E reaches 30 g / L or more, the lithium-rich brine E is introduced into a boron ore pool, and industrial hydrochloric acid is added for mixed reaction to precipitate crude boron ore, and the amount used should be 1.1 times the theoretical calculated value; when lithium salt begins to precipitate, solid-liquid separation is performed, and 620 kg of lithium-rich brine F is obtained after solid-liquid separation, and the process returns to step S4 until the lithium content of the lithium-rich brine E reaches 25-27 g / L and the borate content is less than 10 g / L, and 395 kg of lithium-rich brine F is obtained;

[0165] S6. When the lithium content of the above 395 kg lithium-rich brine F reaches 25-27 g / L and the borate content is less than 10 g / L, add an excess of soda ash solution, the amount of which is 1.2 times the theoretical value, stir evenly, and precipitate and crystallize at 80-100 ° C. The obtained crystals are washed and dried to obtain 44 kg of finished industrial-grade lithium carbonate and 800 kg of lithium precipitation mother liquor G. The lithium content of the lithium precipitation mother liquor reaches 2-4 g / L.

[0166] S7, 800 kg of lithium precipitation mother liquor G is combined with purified brine B to enter step S2, and mixed salts such as sodium chloride and potassium chloride in the lithium precipitation mother liquor are removed to increase the concentration of lithium salt in the lithium-rich brine, thereby increasing the purity and length of the capillary crystallized lithium salt of the fiber rope group, and collecting the salt shell of the lithium salt at the top of the fiber rope group in step S4 to obtain lithium-rich solid H.

[0167] Industrial-grade lithium carbonate and lithium-rich solid H2 are combined, and the total yield of process lithium ions is calculated to be 77%.

[0168] Implementation Case 5:

[0169] The salt lake brine used in this embodiment is raw brine of a carbonate salt lake, wherein the concentration of lithium in the raw brine of the carbonate salt lake is 0.7 g / L, the concentration of carbonate is 30 g / L, the concentration of sulfate is 7 g / L, and the concentration of boron trioxide is 8 g / L.

[0170] S1. After the original brine A is filtered through a grid, naturally settled, and sand filtered, the silt and suspended matter in the brine are removed. The trace amount of calcium and magnesium in the brine is removed through a polystyrene ion exchange resin modified with aminoacetate to obtain a purified brine B, in which Mg 2+≤0.02ppm and Ca 2+≤0.02ppm. After the resin is saturated, it is regenerated into a hydrogen form using hydrochloric acid or sulfuric acid and then regenerated into a sodium form using sodium hydroxide;

[0171] S2, each time taking 600kg of purified brine B into the rock salt capillary crystallization evaporation chamber, placing it in the environmental simulation, adjusting the temperature of the evaporation pool to control the brine pool temperature at 25-30°C, controlling the capillary crystallization temperature of the fiber rope group at 25-35°C through the cold and hot fan exhaust and lighting equipment, monitoring the evaporation process, monitoring the Li+ concentration and K+ concentration in the brine, when the potassium chloride precipitated on the fiber rope group accounts for 85-90% of the salt crust component, stop this stage of capillary crystallization and high-temperature evaporation, obtain 39kg of solid salt ore (mainly sodium chloride, etc.), the fiber rope group precipitates 5kg of salt crust (mainly sodium chloride, potassium chloride, etc.), and obtain 100kg of lithium-rich brine C, the lithium content concentration reaches 4-4.5g / L;

[0172] S3, each time take 600kg lithium-rich brine C into the low-temperature capillary crystallization evaporation chamber, the brine pool low-temperature evaporation and freezing denitrification, put it in the environmental simulation, adjust the temperature of the evaporation pool, the brine pool temperature is controlled at 4 ~ 10 ℃ low-temperature evaporation, the fiber rope group above the evaporation pool crystallization temperature is 10 ~ 15 ℃, the fiber rope group on the fiber rope group precipitation of mirabilite or potassium mirabilite accounted for 40 ~ 50% of the salt crust components, replace the new fiber rope group; control the temperature of the brine pool at -8 ~ -6 ℃, cool -0.5 ℃, place for 6 hours, steam Then, the saltpeter and potassium glauber's salt are precipitated from the pool, and the solid salt ore is discharged in time; the low-temperature evaporation, cooling and placement, and capillary crystallization process are repeated (1 to 2 times) until the lithium chloride and lithium sulfate precipitated on the fiber rope group account for 10 to 15% of the salt crust, and the capillary crystallization and low-temperature evaporation at this stage are stopped to obtain 11 kg of solid salt ore (mainly saltpeter and potassium glauber's salt, etc.), salt crust precipitated from the fiber rope group (mainly potassium chloride, saltpeter, sodium chloride, etc.), and 180 kg of lithium-rich brine D with a lithium content of 13 to 17 g / L;

[0173] S4, each time taking 600kg lithium-rich brine D into the lithium salt capillary crystallization evaporation chamber, placing it in the environmental simulation, adjusting the temperature of the evaporation pool to control the brine pool temperature at 25-30°C, controlling the capillary crystallization temperature of the fiber rope group at 25-35°C by exhausting hot and cold fans, monitoring the evaporation process, monitoring the Li+ concentration in the brine, the fiber rope begins to precipitate lithium chloride salt shell (a small part of lithium sulfate) about 0.8m above the liquid surface, and replacing the saturated fiber rope group in time. When the Li+ concentration in the brine reaches 20-22g / L, stop this stage of capillary crystallization and evaporation, and obtain 2kg of solid salt ore (mainly potassium salt, a small part of lithium carbonate, etc.), the fiber rope group precipitates 4kg of salt shell (mainly lithium carbonate, lithium chloride, lithium-rich solid H), and obtains 396kg of lithium-rich brine E, the lithium content concentration reaches 25-30g / L, and the borate concentration reaches 30g / L at this time;

[0174] S5. When the borate concentration in the lithium-rich brine E reaches 30 g / L or more, the lithium-rich brine E is introduced into a boron ore pool, and industrial hydrochloric acid is added for mixed reaction to precipitate crude boron ore. The amount used should be 1.1 times the theoretical calculated value. When lithium salt begins to precipitate, solid-liquid separation is performed. After solid-liquid separation, 620 kg of lithium-rich brine F is obtained, and the process returns to step S4 until the lithium content of the lithium-rich brine E reaches 27-30 g / L and the borate content is less than 5 g / L, and 380 kg of lithium-rich brine F is obtained.

[0175] S6. When the lithium content of the above 380kg lithium-rich brine F reaches 27-30g / L and the borate content is less than 5g / L, add an excess of soda ash solution, the amount of which is 1.2 times the theoretical value, stir evenly, and precipitate and crystallize at 80-100°C. The obtained crystals are washed and dried to obtain 45.5kg of finished industrial-grade lithium carbonate and 800kg of lithium precipitation mother liquor G. The lithium content of the lithium precipitation mother liquor reaches 2-4g / L.

[0176] S7, 800 kg of lithium precipitation mother liquor G is combined with purified brine B to enter step S2, and mixed salts such as sodium chloride and potassium chloride in the lithium precipitation mother liquor are removed to increase the concentration of lithium salt in the lithium-rich brine, thereby increasing the purity and length of the capillary crystallized lithium salt of the fiber rope group, and collecting the salt shell of the lithium salt at the top of the fiber rope group in step S4 to obtain lithium-rich solid H.

[0177] Industrial-grade lithium carbonate and lithium-rich solid H2 are combined, and the total yield of process lithium ions is calculated to be 78.5%.

[0178] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0179] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0180] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for separating lithium salt from carbonate brine, characterized in that: include: S1, pre-treating the original brine A, then removing the suspended matter and calcium and magnesium to obtain brine B; S2, discharge brine B into the crystallization evaporation chamber for evaporation concentration and capillary crystallization, and the hydrophilic porous fiber rope group and the evaporation pool body precipitate sodium chloride and potassium chloride to obtain lithium-rich brine C; S3, discharge the lithium-rich brine C into a low-temperature crystallization evaporation chamber for low-temperature evaporation, freezing denitrification and capillary crystallization, use the pool body to precipitate sodium chloride, potassium chloride, sodium chloride and potassium chloride to obtain lithium-rich brine D; S4, discharge the lithium-rich brine D into the lithium salt crystallization evaporation chamber for evaporation concentration and capillary crystallization, use the pool body to precipitate sylvite, and use the fiber rope group to precipitate lithium-rich solid H to obtain lithium-rich brine E; S5, when the borate concentration in the lithium-rich brine E reaches a predetermined value, a boron ore pool is introduced, fresh water or original brine or industrial acid is added for mixed reaction, crude boron ore is precipitated, and solid-liquid separation is performed when lithium salt begins to precipitate, and lithium-rich brine F is obtained after solid-liquid separation; S6, adding an excess of soda ash solution to the lithium-rich brine F, stirring evenly, and precipitating and crystallizing at 80-100° C., washing and drying the obtained crystals to obtain finished industrial-grade lithium carbonate, and obtaining lithium precipitation mother liquor G; S7, the lithium precipitation mother liquor G and the purified brine B enter the S2 step together to remove the sodium chloride and potassium chloride therein.

2. The method for separating lithium salt from carbonate brine according to claim 1, characterized in that: The original halide A has a lithium ion content of 0.05-20 g / L, a sodium ion content of 5-160 g / L, a magnesium ion content of 0.1-10 g / L, a boron ion content of 0.01-5 g / L, a carbonate ion content of 10-80 g / L, a chloride ion content of 15-154 g / L, a sulfate content of 5-20 g / L, and a pH of 8-11.

3. The method for separating lithium salt from carbonate brine according to claim 1, characterized in that: In step S1, the step of pretreating the raw halide A includes: removing silt or organic matter by at least one method selected from the group consisting of grid filtration, natural sedimentation, chemical flocculation, sand filtration, activated carbon adsorption, and ultrafiltration; and removing suspended matter and calcium and magnesium by passing the pretreated raw halide A through an ion exchange resin, wherein the ion exchange resin is a polystyrene resin modified by aminoacetate or aminophosphate.

4. The method for separating lithium salt from carbonate brine according to claim 1, characterized in that: The evaporation process in the carbonate brine lithium salt separation method is achieved through the following steps: Obtain the density and composition of brine in each step; According to the density and composition of the obtained brine, the actual evaporation amount, temperature, humidity and capillary crystallization length of the brine in the corresponding capillary crystallization chamber are adjusted; Control different salts in different brines to crystallize in different evaporation and crystallization chambers and different areas and height positions of fiber rope groups; Collect lithium salts and other salts separately.

5. The method for separating carbonate-type brine lithium salt according to claim 1, characterized in that: The fiber rope group is prepared by the following method: Select one or more combinations of cellulose acetate, polyamide, polyacrylonitrile, and polyethylene terephthalate; The selected materials are blended and modified, or modified by adding a hydrophilic or hydrophobic modifier, wherein the hydrophilic contact angle of the hydrophilic porous fiber is in the range of 0-80°; The modified material is used to make a hydrophilic porous fiber rope group.

6. The method for separating lithium salt from carbonate brine according to claim 5, characterized in that: The hydrophilic contact angle of the hydrophilic porous fiber ranges from 20 to 60°.

7. The method for separating lithium salt from carbonate brine according to claim 1, characterized in that: In steps S2 and S4, the temperature of the liquid brine is between 10.0°C and 40.0°C, and the capillary crystallization temperature is between 15.0°C and 35.0°C; in step S3, the temperature of the low-temperature evaporation liquid brine is between 4°C and 10°C, the temperature of the frozen denitrification liquid brine is between -8.0°C and -4.0°C, and the capillary crystallization temperature is between 10.0°C and 20.0°C.

8. The method for separating lithium salt from carbonate brine according to claim 1, characterized in that: In step S5, the predetermined value of the borate concentration is greater than or equal to 30 g / L, the volume ratio of the lithium-rich brine E to the fresh water or the original brine is 50:100 to 300:100, and the industrial acid is hydrochloric acid or sulfuric acid, and the amount used is 1 to 1.1 times the theoretical calculated value of the industrial acid.

9. The method for separating lithium salt from carbonate brine according to claim 1, characterized in that: In step S6, the mass concentration of Li+ in the lithium-rich brine F is greater than 20-30 g / L, and the molar ratio of carbonate ions to lithium ions in the mixed solution is 1-1.2:

2.

10. The method for separating lithium salt from carbonate brine according to claim 1, characterized in that: After step S7, the method further includes: dissolving and purifying the lithium-rich solid H; or, The lithium-rich solid H is added to step S6 to precipitate lithium.

11. A carbonate brine lithium salt separation system, applied to the carbonate brine lithium salt separation method according to any one of claims 1 to 10, characterized in that: A crystallization evaporation chamber is included, wherein the crystallization evaporation chamber comprises: Brine pond (1); A lithium extraction device (2) comprises a hydrophilic porous fiber rope group, and the lithium extraction device (2) can be moved to different brine pools for crystallization and salt precipitation; An evaporation and insulation chamber (3), wherein the brine pool and the lithium extraction device (2) are both located in the evaporation and insulation chamber (3), and the evaporation and insulation chamber (3) is used to adjust the evaporation temperature and humidity; A control system (4) is used to control the salt precipitation parameters in the brine pool (1) and the evaporation and insulation chamber (3).

12. The carbonate brine lithium salt separation system according to claim 11, characterized in that: The brine pool (1) comprises a primary brine pool (101), a secondary brine pool (102) and a tertiary brine pool (103), each brine pool being provided with a brine mixing device (11) and a brine heating module (12), the lithium extraction device (2) also comprising a square grid mesh (13) and a grid frame (24), the top end of the hydrophilic porous fiber rope group being connected to the grid frame (24), and the bottom end being connected to the square grid mesh (13).

13. The carbonate brine lithium salt separation system according to claim 11, characterized in that: The hydrophilic porous fiber rope group comprises a plurality of porous fiber ropes (21) arranged in parallel, wherein the porous fiber rope (21) comprises a steel wire rope core (211), a porous fiber bundle (212) and a multi-strand fiber winding bundle (213), wherein the porous fiber bundle (212) is braided and wound around the outer periphery of the steel wire rope core (211), and the multi-strand fiber winding bundle (213) is wound around the outer periphery of the porous fiber bundle (212), and the porous fiber bundle (212) is wound and fixed.

14. The carbonate brine lithium salt separation system according to claim 11, characterized in that: The lithium extraction device (2) also includes a lifting and moving device (23) arranged on the top of the hydrophilic porous fiber rope group, and a rope head fixing and unlocking device (22) is also arranged on the top of the hydrophilic porous fiber rope group. The hydrophilic porous fiber rope group is detachably connected to the lifting and moving device (23) through the rope head fixing and unlocking device (22).

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