Method for producing lithium-containing compound by using chloride type low-lithium brine

Abstract

The invention provides a method for producing a lithium-containing compound by using chloride type low-lithium brine, which comprises the following steps: a first adsorption stage: obtaining a first purified solution, a second purified solution and a third purified solution; a second adsorption stage: obtaining an adsorption purification solution; and sequentially carrying out reverse osmosis concentration, extraction, back extraction and post-treatment on the adsorption purification liquid to obtain the lithium-containing compound. According to the scheme for preparing the high-purity lithium-containing compound with low cost and short process, the secondary adsorption stage in the process of extracting lithium from the brine is designed, so that the yield of lithium is greatly improved, impurities such as sodium, potassium and magnesium are effectively removed, the concentration of lithium ions is also remarkably improved, and the quality of lithium is improved. And the purposes of lithium ion enrichment and concentration and impurity removal of the ultra-low salt lake brine are achieved.

Description

Technical Field

[0001] The invention relates to the field of lithium extraction from brine, and in particular to a method for producing lithium-containing compounds by utilizing chloride-type low-lithium brine. Background Art

[0002] Lithium is a key inorganic element with important industrial uses. Currently, lithium mainly comes from salt lake brine, ore and recycled lithium metal. In particular, salt lake brine contains a large amount of lithium, but the cost of extracting lithium from brine is high and the grade is low.

[0003] To extract lithium from salt lake brine, adsorption, extraction, precipitation, membrane and other methods are currently used. Among them, adsorption is one of the main methods for extracting lithium from brine, which mainly uses ion exchange resin or ion sieve to selectively adsorb lithium from brine, and obtains a solution with low impurity content such as magnesium after washing and desorption, and then deeply removes impurities associated with salt lake brine such as boron, calcium and magnesium, and then concentrates and precipitates lithium with sodium carbonate.

[0004] However, the adsorption method for extracting lithium from brine has problems due to the low grade and content of lithium in the brine. At the same time, the adsorption capacity of the adsorbent used is generally small, resulting in a long process flow and high energy consumption. At the same time, the lithium recovery rate is low and the cost is relatively high.

[0005] Based on this, how to optimize the extraction of lithium from salt lake brine by adsorption method to improve the lithium recovery rate, shorten the process flow, reduce the preparation cost, and prepare high-purity lithium-containing compound products is one of the important technical problems that need to be solved in this field. Summary of the invention

[0006] The main purpose of the present invention is to provide a method for producing lithium-containing compounds using chloride-type low-lithium brine and lithium-containing compounds, so as to solve the problems of long process flow and high cost of lithium extraction from chloride-type low-lithium brine in the prior art.

[0007] In order to achieve the above-mentioned purpose, the present invention provides a method for producing lithium-containing compounds using chloride-type low-lithium brine, comprising: step S1, a first adsorption stage: step S1-1, pumping the chloride-type low-lithium brine into a first adsorption column, performing a first adsorption, and obtaining a second adsorption column; step S1-2, using water as a first top-loading liquid, performing a first top-loading on the second adsorption column, and obtaining a first waste liquid and a third adsorption column; step S1-3, using water as a first desorption liquid, and sequentially performing a first desorption, a second desorption, and a third desorption on the third adsorption column, and obtaining a fourth adsorption column; wherein the first desorption, the second desorption, and the third desorption respectively obtain a first purified liquid, a second purified liquid, and a third purified liquid; step S1-4, pumping fresh chloride-type low-lithium brine into the fourth adsorption column, performing displacement, and obtaining a first waste liquid. Five adsorption columns; step S2, the second adsorption stage: step S2-1, the first purified liquid, the second purified liquid and the third purified liquid are used together as the second top feed liquid to perform the second top feed on the fifth adsorption column to obtain the second waste liquid and the sixth adsorption column; step S2-2, water is used as the second analytical liquid, and the sixth adsorption column is sequentially subjected to the fourth desorption, the fifth desorption and the sixth desorption; wherein the fourth desorption, the fifth desorption and the sixth desorption respectively obtain the fourth purified liquid, the fifth purified liquid and the sixth purified liquid, which are mixed to obtain the adsorption purified liquid; step S3, the adsorption purified liquid is subjected to reverse osmosis concentration to obtain a concentrated liquid; step S4, the concentrated liquid is sequentially subjected to extraction and back extraction to obtain a lithium-containing solution; step S5, the lithium-containing solution is post-treated to obtain a lithium-containing compound.

[0008] Furthermore, in the chloride-type low-lithium brine, the lithium ion concentration is 60 mg / L to 900 mg / L, the sodium ion concentration is 1000 mg / L to 90000 mg / L, the potassium ion concentration is 1000 mg / L to 18000 mg / L, and the magnesium ion concentration is 40000 mg / L to 120000 mg / L; preferably, in step S1-1, the chloride-type low-lithium brine is pumped into the first adsorption column at a flow rate of 10 Bv / h to 12 Bv / h; and / or, the first adsorption time is 12±2 min.

[0009] Further, in step S1-3, during the first desorption, the second desorption and the third desorption, the pumping flow rate of the first desorption liquid is independently 3.5 Bv / h to 5.0 Bv / h, and the temperature is independently 35°C to 40°C; preferably, the time of the first desorption, the second desorption and the third desorption is independently 12±2 min; more preferably, in the first purified solution, the lithium ion concentration is 200 mg / L to 500 mg / L, the sodium ion concentration is 30 mg / L to 100 mg / L, the potassium ion concentration is 5 mg / L to 10 mg / L, and the magnesium ion concentration is 100 mg / L~300mg / L; and / or, in the second purified solution, the lithium ion concentration is 300mg / L~700mg / L, the sodium ion concentration is 20mg / L~30mg / L, the potassium ion concentration is 5mg / L~15mg / L, and the magnesium ion concentration is 150mg / L~300mg / L; and / or, in the third purified solution, the lithium ion concentration is 400mg / L~700mg / L, the sodium ion concentration is 20mg / L~30mg / L, the potassium ion concentration is 5mg / L~15mg / L, and the magnesium ion concentration is 100mg / L~300mg / L.

[0010] Further, in step S1-4, the replacement includes: pumping the chloride-type low-lithium brine into the fourth adsorption column at a flow rate of 1Bv / h to 2Bv / h for a first replacement; pumping the chloride-type low-lithium brine into the fourth adsorption column again at a flow rate of 11Bv / h to 12Bv / h for a second replacement; preferably, the time for the first replacement and the second replacement is independently 12±2min.

[0011] Furthermore, step S2-1 also includes: mixing the first purified liquid, the second purified liquid and the third purified liquid in a volume ratio of (4-5):1:1 to obtain a mixed purified liquid, and using the mixed purified liquid as the second top feed liquid; preferably, the pumping flow rate of the second top feed liquid is 6Bv / h-8Bv / h; more preferably, the time of the second top feed is 12±2min.

[0012] Further, in step S2-2, during the fourth desorption, the fifth desorption and the sixth desorption, the pumping flow rate of the second desorption liquid is independently 3.5 Bv / h to 5.0 Bv / h, and the temperature is independently 40±2°C; preferably, the time of the fourth desorption, the fifth desorption and the sixth desorption is independently 12±2 min; more preferably, in the fourth purified liquid, the lithium ion concentration is 400 mg / L to 1700 mg / L, the sodium ion concentration is 100 mg / L to 200 mg / L, the potassium ion concentration is 15 mg / L to 40 mg / L, and the magnesium ion concentration is 500 mg / L~800mg / L; and / or, in the fifth purified solution, the lithium ion concentration is 500mg / L~700mg / L, the sodium ion concentration is 20mg / L~70mg / L, the potassium ion concentration is 5mg / L~15mg / L, and the magnesium ion concentration is 150mg / L~300mg / L; and / or, in the sixth purified solution, the lithium ion concentration is 700mg / L~800mg / L, the sodium ion concentration is 20mg / L~70mg / L, the potassium ion concentration is 5mg / L~15mg / L, and the magnesium ion concentration is 150mg / L~300mg / L.

[0013] Furthermore, in step S3, the pressure of reverse osmosis concentration is 3.5 MPa to 4.5 MPa.

[0014] Further, step S4 comprises: adjusting the pH value of the concentrated solution to 12-13 and filtering to obtain a filtrate, and then extracting and stripping the filtrate in sequence to obtain a lithium-containing solution; preferably, during the extraction process, the weight ratio of the filtrate to the extractant is (3-4):1; and / or, during the stripping process, the stripping agent used is one of carbon dioxide, hydrochloric acid solution and phosphoric acid solution.

[0015] Furthermore, the stripping agent is carbon dioxide, and the post-treatment in step S5 is heating filtration; and / or, the stripping agent is hydrochloric acid solution or phosphoric acid solution, and the post-treatment in step S5 is evaporation crystallization.

[0016] The technical solution of the present invention provides a solution for preparing high-purity lithium-containing compounds with low cost and short process based on salt lake brine with low lithium concentration. By designing the secondary adsorption stage in the process of lithium extraction from brine, the lithium yield is greatly improved, and impurities such as sodium, potassium and magnesium are effectively removed. At the same time, the concentration of lithium ions is also significantly improved, thereby achieving the purpose of enriching, concentrating and removing impurities of lithium ions in ultra-low salt lake brine, and reducing the cost of preparing lithium-containing compound products using salt lake chloride-type low-lithium brine as raw material. DETAILED DESCRIPTION

[0017] 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 in conjunction with the embodiments.

[0018] As described in the background technology, there is a problem in the prior art that it is difficult to use chloride-type low-lithium brine as a raw material, recover it through adsorption, and produce high-purity lithium-containing compounds. In order to solve the above technical problems, the present invention provides a method for producing lithium-containing compounds using chloride-type low-lithium brine, including: step S1, the first adsorption stage: step S1-1, pumping the chloride-type low-lithium brine into the first adsorption column, performing the first adsorption, and obtaining the second adsorption column; step S1-2, using water as the first top-loading liquid, performing the first top-loading on the second adsorption column, and obtaining the first waste liquid and the third adsorption column; step S1-3, using water as the first desorption liquid, and sequentially performing the first desorption, the second desorption, and the third desorption on the third adsorption column to obtain the fourth adsorption column; wherein the first desorption, the second desorption, and the third desorption respectively obtain the first purified liquid, the second purified liquid, and the third purified liquid; step S1-4, pumping fresh chloride-type low-lithium brine into the fourth adsorption column for replacement, and obtaining A fifth adsorption column; step S2, a second adsorption stage: step S2-1, using the first purified liquid, the second purified liquid and the third purified liquid together as the second top feed liquid, performing the second top feed on the fifth adsorption column to obtain a second waste liquid and a sixth adsorption column; step S2-2, using water as the second analytical liquid, sequentially performing a fourth desorption, a fifth desorption and a sixth desorption on the sixth adsorption column; wherein the fourth desorption, the fifth desorption and the sixth desorption respectively obtain a fourth purified liquid, a fifth purified liquid and a sixth purified liquid, which are mixed to obtain an adsorption purified liquid; step S3, performing reverse osmosis concentration on the adsorption purified liquid to obtain a concentrated liquid; step S4, extracting and back-extracting the concentrated liquid in turn to obtain a lithium-containing solution; step S5, post-treating the lithium-containing solution to obtain a lithium-containing compound.

[0019] The present invention uses chloride-type low-lithium brine as a raw material, and sequentially performs step-by-step secondary adsorption, reverse osmosis concentration, extraction and back extraction to obtain a lithium-containing solution, and then obtains a high-purity lithium-containing compound through post-treatment. In particular, for the design of step-by-step secondary adsorption, in the first adsorption stage, chloride-type low-lithium brine is used as a raw material (hereinafter referred to as raw brine), and through adsorption, top loading, desorption, and replacement, a first purified liquid, a second purified liquid, and a third purified liquid with a high lithium content are obtained, and a fifth adsorption column refilled with raw brine is obtained at the same time. Specifically:

[0020] In the first adsorption process, the raw brine is pumped into the first adsorption column filled with adsorbent. When it contacts the adsorbent, the lithium ions undergo chemical or physical adsorption with the active sites on the surface of the adsorbent, and are thus adsorbed from the brine. At the same time, since the adsorbent has a weak adsorption capacity for sodium, potassium and magnesium ions, they are basically not adsorbed, but flow out of the adsorption column with the tail liquid during the first top-up process. Afterwards, the third adsorption column adsorbed with a large amount of lithium ions is adsorbed again using a higher concentration of lithium-containing solution to obtain a fourth adsorption column, and the first purified liquid, the second purified liquid and the third purified liquid are obtained in sequence. In this process, water, i.e., the first desorption liquid, is pumped into the third adsorption column and contacts the adsorbent, and the lithium ions are desorbed from the surface of the adsorbent and enter it, forming a high-concentration lithium solution. In particular, the present invention sets the first desorption, the second desorption and the third desorption to be performed in sequence in this process, so as to more thoroughly desorb and bring out the lithium ions in the adsorption column.

[0021] In the first adsorption process, the first purified liquid, the second purified liquid and the third purified liquid obtained above are used together as the second top feed liquid, which can significantly improve the recovery rate of lithium in the original brine and the content of lithium in the desorption liquid, reduce its loss, reduce the impurity content, and also save water and maintain the stability of the adsorbent in the adsorption column. In particular, after the first adsorption stage, the concentration of lithium ions in the three purified liquids obtained is much higher than that in the original brine. When it is used as the top feed liquid, due to its high lithium ion concentration, it can effectively promote the re-adsorption of lithium ions on the adsorbent, thereby improving the total recovery rate of lithium and the concentration of lithium in the desorption liquid. Compared with the use of pure water, the lithium ion concentration in pure water is close to zero, and no additional driving force can be provided to promote the re-adsorption of lithium ions on the adsorbent. At the same time, since the concentrations of impurities such as sodium, potassium and magnesium in the three purified liquids obtained have been significantly reduced, the residual impurities on the adsorbent can be further replaced, reducing the content of impurities in the subsequent treatment process. Compared with the use of water as the second top feed liquid, although pure water is clean, it is not as effective as the purified liquid containing certain impurities in replacing impurities. Therefore, using purified liquid as the second top feed liquid can more effectively improve the lithium yield and the lithium concentration in the desorption liquid, and cooperate with subsequent reverse osmosis concentration, extraction, back extraction and post-treatment to obtain lithium-containing compounds with higher purity and lower preparation cost.

[0022] In summary, the above method provided by the present invention significantly reduces impurities such as sodium, potassium and magnesium in chloride-type low-lithium brine, significantly improves the concentration of lithium ions in the desorption solution, achieves the purpose of enriching, concentrating and removing impurities of lithium ions therein, significantly reduces the cost of preparing lithium-containing compound products using salt lake chloride-type low-lithium brine as raw material, shortens the process of preparing lithium salt compounds, and also prepares high-purity lithium-containing compound products.

[0023] In practical applications, the adsorption column used in the above method is filled with an aluminum-based adsorbent, specifically LiCl·nAl(OH)3·mH2O, and the coefficients n and m are the molar numbers of the compounds of aluminum hydroxide and water in the adsorbent, respectively, which vary depending on the preparation process and are usually independently 1 to 3. The adsorption column is a common adsorption tank, which usually contains a liquid distributor inside, which is used to evenly distribute the liquid in the adsorption column and protect the adsorbent from loss.

[0024] Furthermore, in the chloride-type low-lithium brine, the lithium ion concentration is 60mg / L~900mg / L, the sodium ion concentration is 1000mg / L~90000mg / L, the potassium ion concentration is 1000mg / L~18000mg / L, and the magnesium ion concentration is 40000mg / L~120000mg / L. The above-mentioned control and optimization of the original brine composition is more suitable for the above-mentioned method provided by the present invention, so that it can more effectively promote the efficient secondary adsorption and desorption process, while reducing the interference of impurity ions at each stage on lithium ion recovery, thereby improving its recovery effect. In practical applications, the treated chloride-type low-lithium brine comes from the intercrystalline brine of the Chaka Salt Lake in the Qaidam Basin (that is, high-concentration brine filled in the pores of the salt layer of the salt lake deposit).

[0025] In several more typical embodiments, in the chloride-type low-lithium brine, the lithium ion concentration is 60 mg / L to 900 mg / L, the sodium ion concentration is 1000 mg / L to 90000 mg / L, the potassium ion concentration is 1000 mg / L to 18000 mg / L, and the magnesium ion concentration is 40000 mg / L to 120000 mg / L; in order to improve the adsorption efficiency in the first adsorption process and enhance the adsorption effect of lithium ions, the flow rate and adsorption time of the raw brine when pumped into the first adsorption column are preferably selected, that is, preferably: in step S1-1, the chloride-type low-lithium brine is pumped into the first adsorption column at a flow rate of 10 Bv / h to 12 Bv / h; and / or the first adsorption time is 12±2 min.

[0026] Furthermore, for the desorption process of the first adsorption stage, the inventors have optimized through a large number of experiments that the pumping flow rate of the first desorption liquid is independently 3.5Bv / h to 5.0Bv / h, and the temperature is independently 35°C to 40°C during the first desorption, second desorption and third desorption. The above-mentioned flow rate and temperature control of the first desorption liquid can more effectively improve the desorption rate of lithium ions during the first adsorption stage, reduce the loss of lithium ions during the desorption process, and obtain the first purified liquid, the second purified liquid and the third purified liquid with higher lithium ion content and less impurity content, and use the three as the top feed liquid in the second adsorption stage in a certain proportion, thereby improving the lithium ion concentration of the final lithium-containing desorption liquid and the purity of the lithium-containing compound. At the same time, it is preferred that the time of the first desorption, the second desorption and the third desorption is independently 12±2min, so as to promote the full progress of the first desorption process and reduce the loss of lithium ions caused by excessive desorption.

[0027] In several typical embodiments, in the first purified solution, the lithium ion concentration is 200 mg / L to 500 mg / L, the sodium ion concentration is 30 mg / L to 100 mg / L, the potassium ion concentration is 5 mg / L to 10 mg / L, and the magnesium ion concentration is 100 mg / L to 300 mg / L; and / or, in the second purified solution, the lithium ion concentration is 300 mg / L to 700 mg / L, the sodium ion concentration is 20 mg / L to 30 mg / L, the potassium ion concentration is 5 mg / L to 15 mg / L, and the magnesium ion concentration is 150 mg / L to 300 mg / L; and / or, in the third purified solution, the lithium ion concentration is 400 mg / L to 700 mg / L, the sodium ion concentration is 20 mg / L to 30 mg / L, the potassium ion concentration is 5 mg / L to 15 mg / L, and the magnesium ion concentration is 100 mg / L to 300 mg / L. By optimizing the parameters in the first desorption process, the first purified solution, the second purified solution and the third purified solution with the above-mentioned component contents are obtained, and the lithium ion concentrations in the three solutions increase successively, while the contents of other types of impurity ions decrease gradually. It is preferred that the three solutions with the above-mentioned component contents are used together in a certain proportion as the second top feed solution, so as to better utilize the advantages of high lithium concentration and low impurity concentration, thereby realizing the extraction of lithium from the original brine with a higher recovery rate, and finally preparing a lithium-containing compound product with a higher purity.

[0028] During the replacement process in the first adsorption stage, in order to further improve the recovery rate of lithium ions and reduce the waste of brine, and at the same time obtain a substrate adsorption column that adsorbs a larger amount of lithium ions again, the replacement includes: pumping the chloride-type low-lithium brine at a flow rate of 1Bv / h to 2Bv / h into the fourth adsorption column for the first replacement; pumping the chloride-type low-lithium brine at a flow rate of 11Bv / h to 12Bv / h into the fourth adsorption column again for the second replacement; and / or, the time for the first replacement and the second replacement is independently 12±2min.

[0029] Furthermore, step S2-1 also includes: mixing the first purified liquid, the second purified liquid and the third purified liquid in a volume ratio of (4-5): 1: 1 to obtain a mixed purified liquid, and using the mixed purified liquid as the second top feed liquid. As mentioned above, the present invention can further improve the recovery rate of lithium in the original brine and the lithium ion concentration of the lithium-containing desorption liquid and reduce the impurity content by mixing the three purified liquids in the first adsorption stage as the top feed liquid of the second adsorption stage. The inventors rely on the composition of the obtained first purified liquid, the second purified liquid and the third purified liquid, and further optimize the volume ratio of the above mixing through a large number of experiments, thereby achieving the extraction of lithium from the original brine with a higher recovery rate, and also further prepare a higher purity lithium-containing compound sample with a higher purity.

[0030] In several typical embodiments, the lithium ion concentration in the mixed purified solution is 200 mg / L to 400 mg / L, the sodium ion concentration is 20 mg / L to 150 mg / L, the potassium ion concentration is 5 mg / L to 20 mg / L, and the magnesium ion concentration is 200 mg / L to 800 mg / L. The above optimization of the components of the mixed purified solution can further promote the efficient recovery of lithium ions and improve the purity of the final lithium-containing compound.

[0031] The pumping flow rate of the second top-feeding liquid is preferably 6Bv / h to 8Bv / h, and the second top-feeding time is more preferably 12±2min, which can make the top-feeding process of the second adsorption stage more complete, improve the top-feeding efficiency, and reduce the loss of lithium ions during the top-feeding process. At the same time, the setting of the above parameters can also better adapt to the component concentration of the above-mentioned mixed purified liquid, that is, the second top-feeding liquid, so as to more effectively play the role of the mixed purified liquid in improving the lithium recovery rate.

[0032] And, in step S2-2, during the fourth desorption, the fifth desorption and the sixth desorption, the pumping flow rate of the second desorption liquid is independently 3.5 Bv / h to 5.0 Bv / h, and the temperature is independently 40±2°C; and / or, the time of the fourth desorption, the fifth desorption and the sixth desorption is independently 12±2 min. Preferably, the parameters in the process of obtaining the adsorption purified liquid by final desorption, including the flow rate of the desorption liquid used for each desorption and the temperature and time used, can more effectively improve the desorption rate of lithium ions, reduce the loss of lithium ions during the desorption process, and recover the adsorption purified liquid with higher lithium content and lower impurities by desorption, thereby preparing a lithium-containing compound with higher purity.

[0033] In several typical embodiments, in the fourth purified solution, the lithium ion concentration is 400 mg / L to 1700 mg / L, the sodium ion concentration is 100 mg / L to 200 mg / L, the potassium ion concentration is 15 mg / L to 40 mg / L, and the magnesium ion concentration is 500 mg / L to 800 mg / L; and / or, in the fifth purified solution, the lithium ion concentration is 500 mg / L to 700 mg / L, the sodium ion concentration is 20 mg / L to 70 mg / L, the potassium ion concentration is 5 mg / L to 15 mg / L, and the magnesium ion concentration is 150 mg / L to 300 mg / L; and / or, in the sixth purified solution, the lithium ion concentration is 700 mg / L to 800 mg / L, the sodium ion concentration is 20 mg / L to 70 mg / L, the potassium ion concentration is 5 mg / L to 15 mg / L, and the magnesium ion concentration is 150 mg / L to 300 mg / L. The lithium ion content in each adsorption purified liquid obtained through the above steps is higher, so that the purity of the final lithium-containing compound can be more effectively improved. In several more typical embodiments, in the adsorption purified liquid, the lithium ion concentration is 300mg / L~700mg / L, the sodium ion concentration is 40mg / L~250mg / L, the potassium ion concentration is 5mg / L~20mg / L, and the magnesium ion concentration is 200mg / L~1300mg / L. The adsorption purified liquid obtained by the above-mentioned condition parameter optimization has this component content, so that it can better adapt to the subsequent reverse osmosis concentration and extraction process, making it more efficient, while also reducing the interference of impurities on lithium ion recovery, and is more suitable for the high-purity production of lithium compounds.

[0034] In order to more effectively improve the concentration efficiency of lithium ions, reduce energy consumption during the concentration process, and obtain a lithium-containing compound product with higher purity, it is further preferred that in step S3, the pressure of reverse osmosis concentration is 3.5 MPa to 4.5 MPa.

[0035] Further, step S4 includes: adjusting the pH value of the concentrated solution to 12-13 and filtering to obtain a filtrate, and then extracting and stripping the filtrate in sequence to obtain a lithium-containing solution. Accurately adjusting the pH value and filtering the filtrate before extraction can more effectively remove impurities in the filtrate by extraction and stripping, thereby improving the purity of lithium ions and further improving the purity of the lithium compound prepared subsequently.

[0036] During extraction, in order to achieve more efficient enrichment of lithium ions and deeper impurity removal to obtain a lithium-containing compound product with higher purity, the weight ratio of filtrate to extractant is preferably (3-4):1; specifically, the extractant is a crown ether or ionic liquid special lithium extractant, and its structure includes a crown ether main body, a diluent and a co-extractant or a quaternary ammonium salt and other cations, a phosphate anion and a phosphate ester and other functional groups.

[0037] In the process of stripping, the stripping agent used is one of carbon dioxide, hydrochloric acid solution and phosphoric acid solution, so as to obtain lithium carbonate, lithium chloride, lithium phosphate or lithium dihydrogen phosphate products. Furthermore, the stripping agent is carbon dioxide, the post-treatment in step S5 is heating filtration, and the lithium-containing compound is lithium carbonate; and / or, the stripping agent is hydrochloric acid solution, the post-treatment in step S5 is evaporation crystallization, and the lithium-containing compound is lithium chloride; and / or, the stripping agent is phosphoric acid solution, the post-treatment in step S5 is filtration or evaporation crystallization, and the lithium-containing compound is lithium phosphate or lithium dihydrogen phosphate; by using carbon dioxide as a stripping agent, combined with the post-treatment method of heating filtration, high-purity lithium carbonate can be obtained. By using hydrochloric acid solution as a stripping agent, combined with the post-treatment method of evaporation crystallization, high-purity lithium chloride can be obtained. By using phosphoric acid solution as a stripping agent, combined with the post-treatment method of filtration or evaporation crystallization, high-purity lithium phosphate or lithium dihydrogen phosphate can be obtained. The selection of stripping agents and corresponding post-treatment methods can be flexibly adjusted according to different production needs and conditions, and are suitable for customized production of lithium compounds.

[0038] Furthermore, the application of the method shown in this application greatly shortens the process flow, reduces the product preparation cost, and can be widely used in the field of lithium extraction.

[0039] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0040] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0041] Example 1

[0042] A method for producing lithium-containing compounds using chloride-type low-lithium brine:

[0043] The treated chloride-type low-lithium brine comes from the brine of the Qarhan Salt Lake, and contains: a lithium ion concentration of 80 mg / L, a sodium ion concentration of 50400 mg / L, a potassium ion concentration of 8200 mg / L, and a magnesium ion concentration of 42000 mg / L.

[0044] The adsorption column used is filled with a special lithium adsorbent, whose structural formula is LiCl·nAl(OH)3·mH2O, wherein n=2, m=1.5-8.

[0045] (1) The first adsorption stage:

[0046] (1-1) After filtering, the chloride-type low-lithium brine is pumped into the first adsorption column at a flow rate of 11.25 Bv / h for a first adsorption time of 12 minutes to obtain a second adsorption column;

[0047] (1-2) using water as the first top-loading liquid, pumping it into the second adsorption column at a flow rate of 6.9 Bv / h, performing the first top-loading on the second adsorption column for 12 min, and obtaining the first waste liquid and the third adsorption column;

[0048] (1-3) Using 35° C. water as the first desorption liquid, the third adsorption column is subjected to the first desorption, the second desorption and the third desorption in sequence to obtain a fourth adsorption column.

[0049] During the first desorption, the second desorption and the third desorption, the first desorption liquid was pumped into the third adsorption column at a flow rate of 4.5 Bv / h, and the time was 12 minutes. After three desorptions, the first purified liquid, the second purified liquid and the third purified liquid were obtained in turn. Among them:

[0050] In the first purified solution, the lithium ion concentration is 315 mg / L, the sodium ion concentration is 30 mg / L, the potassium ion concentration is 8.2 mg / L, and the magnesium ion concentration is 277 mg / L;

[0051] In the second purified solution, the lithium ion concentration is 370 mg / L, the sodium ion concentration is 22 mg / L, and the potassium ion concentration is

[0052] 8.15mg / L, magnesium ion concentration is 172mg / L;

[0053] In the third purified solution, the lithium ion concentration is 397 mg / L, the sodium ion concentration is 21 mg / L, and the potassium ion concentration is

[0054] 8.02mg / L, magnesium ion concentration is 116mg / L;

[0055] (1-4) pumping the original brine, i.e., chloride-type low-lithium brine, into the fourth adsorption column again at a flow rate of 1.5 Bv / h, and performing a first replacement for 12 minutes; then pumping the chloride-type low-lithium brine into the fourth adsorption column again at a flow rate of 11.25 Bv / h, and performing a second replacement for 12 minutes, to obtain a fifth adsorption column;

[0056] (2) The second adsorption stage:

[0057] (2-1) The first purified liquid, the second purified liquid and the third purified liquid were mixed in a volume ratio of 4:1:1 to obtain a mixed purified liquid, and the mixed purified liquid was used as a second top feed liquid and pumped into the fifth adsorption column at a flow rate of 6 Bv / h for a second top feed for 12 minutes to obtain a second waste liquid and a sixth adsorption column;

[0058] (2-2) Use 40°C water as the second desorption liquid, pump it into the sixth adsorption column at a flow rate of 4.5 Bv / h, and perform the fourth desorption, the fifth desorption and the sixth desorption in sequence to obtain the fourth adsorption column. The time of these three desorptions is 12 minutes, and the fourth purified liquid, the fifth purified liquid and the sixth purified liquid are obtained in sequence, and after mixing, the adsorption purified liquid is finally obtained. Among them:

[0059] In the fourth purified liquid, the lithium ion concentration is 449 mg / L, the sodium ion concentration is 128 mg / L, the potassium ion concentration is 15 mg / L, and the magnesium ion concentration is 567 mg / L;

[0060] In the fifth purified solution, the lithium ion concentration is 670 mg / L, the sodium ion concentration is 22 mg / L, and the potassium ion concentration is

[0061] 8.15mg / L, magnesium ion concentration is 172mg / L;

[0062] In the sixth purified solution, the lithium ion concentration is 727 mg / L, the sodium ion concentration is 21 mg / L, and the potassium ion concentration is

[0063] 7.02mg / L, magnesium ion concentration is 156mg / L;

[0064] (3) The adsorption purified liquid obtained in the above adsorption step is concentrated by a reverse osmosis membrane system, and the pressure of the high-pressure pump is controlled to be 3.5 MPa to obtain a concentrated liquid;

[0065] (4) The pH of the concentrated solution obtained by reverse osmosis is adjusted to 12, and the precipitate is filtered to obtain a filtrate. The obtained filtrate is then mixed with a lithium extractant (dibutyl phosphate) for ionic liquids at a weight ratio of 4:1 (filtrate: extractant) to obtain an extract. The obtained extract is then stripped with carbon dioxide to obtain a lithium-containing solution, i.e., a lithium bicarbonate solution.

[0066] (5) The obtained lithium-containing solution is heated to 80° C., and then the lithium carbonate precipitate is filtered, washed and dried to obtain a lithium carbonate product, i.e., a lithium-containing compound.

[0067] Example 2

[0068] A method for producing lithium-containing compounds using chloride-type low-lithium brine:

[0069] The chloride-type low-lithium brine treated and the type of adsorption column used are consistent with those in Example 1.

[0070] (1) The first adsorption stage:

[0071] (1-1) After filtering, the chloride-type low-lithium brine is pumped into a first adsorption column at a flow rate of 12 Bv / h for a first adsorption time of 12 min to obtain a second adsorption column;

[0072] (1-2) using water as the first top-loading liquid, pumping it into the second adsorption column at a flow rate of 7.7 Bv / h, performing the first top-loading on the second adsorption column for 12 min, and obtaining the first waste liquid and the third adsorption column;

[0073] (1-3) Using 40° C. water as the first desorption liquid, the third adsorption column is subjected to the first desorption, the second desorption and the third desorption in sequence to obtain a fourth adsorption column.

[0074] During the first desorption, the second desorption and the third desorption, the first desorption liquid was pumped into the third adsorption column at a flow rate of 5.0 Bv / h, and the time was 12 minutes. After three desorptions, the first purified liquid, the second purified liquid and the third purified liquid were obtained in turn. Among them:

[0075] In the first purified solution, the lithium ion concentration is 320 mg / L, the sodium ion concentration is 30 mg / L, the potassium ion concentration is 9 mg / L, and the magnesium ion concentration is 280 mg / L;

[0076] In the second purified solution, the lithium ion concentration is 375 mg / L, the sodium ion concentration is 20 mg / L, the potassium ion concentration is 8.5 mg / L, and the magnesium ion concentration is 178 mg / L;

[0077] In the third purified solution, the lithium ion concentration is 420 mg / L, the sodium ion concentration is 20.5 mg / L, and the potassium ion concentration is

[0078] 7.9mg / L, magnesium ion concentration is 120mg / L;

[0079] (1-4) pumping the original brine, i.e., chloride-type low-lithium brine, into the fourth adsorption column again at a flow rate of 1.7 Bv / h, and performing a replacement for 12 minutes, and then pumping the chloride-type low-lithium brine into the fourth adsorption column again at a flow rate of 12 Bv / h, and performing a second replacement for 12 minutes, to obtain a fifth adsorption column;

[0080] (2) The second adsorption stage:

[0081] (2-1) The first purified liquid, the second purified liquid and the third purified liquid were mixed in a volume ratio of 5:1:1 to obtain a mixed purified liquid, and the mixed purified liquid was used as a second top feed liquid and pumped into the fifth adsorption column at a flow rate of 7.3 Bv / h for a second top feed for 12 minutes to obtain a second waste liquid and a sixth adsorption column;

[0082] (2-2) Use 40°C water as the second desorption liquid, pump it into the sixth adsorption column at a flow rate of 5.0 Bv / h, and perform the fourth desorption, the fifth desorption and the sixth desorption in sequence to obtain the fourth adsorption column. The time of these three desorptions is 12 minutes, and the fourth purified liquid, the fifth purified liquid and the sixth purified liquid are obtained in sequence, and after mixing, the adsorption purified liquid is finally obtained. Among them:

[0083] In the fourth purified liquid, the lithium ion concentration is 489 mg / L, the sodium ion concentration is 138 mg / L, the potassium ion concentration is 20 mg / L, and the magnesium ion concentration is 537 mg / L;

[0084] In the fifth purified solution, the lithium ion concentration is 690 mg / L, the sodium ion concentration is 45 mg / L, the potassium ion concentration is 13 mg / L, and the magnesium ion concentration is 202 mg / L;

[0085] In the sixth purified liquid, the lithium ion concentration is 738 mg / L, the sodium ion concentration is 25 mg / L, the potassium ion concentration is 6.5 mg / L, and the magnesium ion concentration is 160 mg / L;

[0086] (3) The adsorption purified liquid obtained in the above adsorption step is concentrated by a reverse osmosis membrane system, and the pressure of the high-pressure pump is controlled to be 4.5 MPa to obtain a concentrated liquid;

[0087] (4) The pH of the concentrated solution obtained by reverse osmosis is adjusted to 12, and the precipitate is filtered to obtain a filtrate. The obtained filtrate is then mixed with a lithium extractant for ionic liquids (quaternary ammonium salt N263) at a weight ratio of 3:1 (filtrate: extractant), and an extract is obtained. The obtained extract is washed with fresh water and then back-extracted with a hydrochloric acid solution to obtain a lithium-containing solution, i.e., a lithium chloride solution.

[0088] (5) The obtained lithium-containing solution is evaporated and crystallized to precipitate lithium chloride, which is then filtered, washed and dried to obtain a lithium chloride product, i.e., a lithium-containing compound.

[0089] Example 3

[0090] A method for producing lithium-containing compounds using chloride-type low-lithium brine:

[0091] The difference between this embodiment and embodiment 1 is only that:

[0092] The flow rate of chloride-type low-lithium brine pumped into the first adsorption column in (1-1) is changed to 8 Bv / h, and the time of the first adsorption is changed to 20 min; at the same time, the flow rate of chloride-type low-lithium brine pumped into the fourth adsorption column in (1-4) is changed to 0.8 Bv / h, and the replacement time is changed to 20 min.

[0093] By using the above-mentioned adsorption and replacement conditions in steps (1-1) and (1-4), a high-purity lithium carbonate product can also be obtained. However, due to the decrease in adsorption efficiency, the yield of the obtained product decreases slightly, so the economic benefit and production value are slightly lower.

[0094] Example 4

[0095] A method for producing lithium-containing compounds using chloride-type low-lithium brine:

[0096] The difference between this embodiment and embodiment 2 is only that:

[0097] The flow rate of chloride-type low-lithium brine pumped into the first adsorption column in (1-1) was changed to 15 Bv / h, and the time of the first adsorption was changed to 5 min. At the same time, the flow rate of chloride-type low-lithium brine pumped into the fourth adsorption column in (1-4) was changed to 0.5 Bv / h, and the replacement time was changed to 5 min.

[0098] Example 5

[0099] A method for producing lithium-containing compounds using chloride-type low-lithium brine:

[0100] The difference between this embodiment and embodiment 2 is only in steps (1-3), specifically:

[0101] Using 20°C water as the first desorption liquid, the third adsorption column is subjected to the first desorption, the second desorption and the third desorption in sequence to obtain the fourth adsorption column. At the same time, during the first desorption, the second desorption and the third desorption, the first desorption liquid is pumped into the third adsorption column at a flow rate of 2Bv / h, and the time is 12 minutes. After three desorptions, the first purified liquid, the second purified liquid and the third purified liquid are obtained in sequence.

[0102] The subsequent steps are the same as those in Example 2.

[0103] Example 6

[0104] A method for producing lithium-containing compounds using chloride-type low-lithium brine:

[0105] The difference between this embodiment and embodiment 2 is only in step (2-1), specifically:

[0106] The first purified liquid, the second purified liquid and the third purified liquid were mixed in a volume ratio of 6:1:1 to obtain a mixed purified liquid, and the mixed purified liquid was used as the second top feeding liquid and pumped into the fifth adsorption column at a flow rate of 3Bv / h for the second top feeding for 20 minutes to obtain the second waste liquid and the sixth adsorption column.

[0107] Example 7

[0108] A method for producing lithium-containing compounds using chloride-type low-lithium brine:

[0109] The difference between this embodiment and embodiment 1 is only in step (2-1), specifically:

[0110] The first purified liquid, the second purified liquid and the third purified liquid were mixed in a volume ratio of 3:2:2 to obtain a mixed purified liquid, and the mixed purified liquid was used as a second top feed liquid and pumped into the fifth adsorption column at a flow rate of 10 Bv / h for a second top feed for 5 minutes to obtain a second waste liquid and a sixth adsorption column.

[0111] In this embodiment, although a high-purity lithium carbonate product can be obtained by changing the volume ratio of the first purified liquid, the second purified liquid and the third purified liquid, as well as the flow rate and time of the pumping after mixing, the recovery rate of lithium is slightly reduced, and the yield is slightly lower than that of Example 1.

[0112] Comparative Example 1

[0113] A method for producing lithium-containing compounds using chloride-type low-lithium brine:

[0114] The difference between this comparative example and Example 1 is only that:

[0115] In step (2-1), water is again used as the second top-loading liquid and pumped into the second adsorption column at a flow rate of 6 Bv / h. The second adsorption column is subjected to the first top-loading for 12 min, and then pumped into the fifth adsorption column at a flow rate of 6 Bv / h for the second top-loading for 12 min to obtain the second waste liquid and the sixth adsorption column.

[0116] The remaining steps are carried out according to Example 1.

[0117] In this comparative example, pure water is used instead of the mixed purified solution in Example 1, and although a high-purity lithium carbonate product can be obtained in the end, on the one hand, the amount of pure water used is too large, and on the other hand, the recovery rate of lithium in the mixed purified solution is significantly reduced, so the yield is significantly reduced, the economic benefits are also significantly reduced, and it is difficult to have practical application value.

[0118] Comparative Example 2

[0119] A method for producing lithium-containing compounds using chloride-type low-lithium brine:

[0120] The difference between this comparative example and Example 2 is only that:

[0121] In step (1-3), the second desorption and the third desorption are not performed, and only the first purified liquid is obtained. In the subsequent step (2-1), the first purified liquid is directly used as the second top feed liquid.

[0122] The remaining steps are carried out according to Example 2.

[0123] Comparative Example 3

[0124] A method for producing lithium-containing compounds using chloride-type low-lithium brine:

[0125] The difference between this comparative example and Example 1 is only that:

[0126] In step (1-3), the third desorption is not performed, and only the first purified liquid and the second purified liquid are obtained. In the subsequent step (2-1), the first purified liquid and the second purified liquid are mixed in a volume ratio of 1:1 as the second top feed liquid.

[0127] The remaining steps are carried out according to Example 1.

[0128] In the above-mentioned embodiments and comparative examples, the contents of various ions in the mixed purified liquid used in the top liquid process of the second adsorption stage, the adsorption purified liquid obtained in the desorption process, and the concentrated liquid obtained in the reverse osmosis concentration stage are shown in Table 1. The purity of the lithium-containing compound finally obtained is also shown in Table 1.

[0129] Table 1

[0130]

[0131]

[0132] From the above description, it can be seen that the above-mentioned embodiment of the present invention realizes the use of chloride-type low-lithium brine as raw material, and prepares high-purity lithium-containing compounds through the first adsorption, the first top feeding, the first desorption, the first replacement, the second top feeding, the second desorption, reverse osmosis concentration, extraction and back extraction, and post-treatment.

[0133] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0134] 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 producing lithium-containing compounds using chloride-type low-lithium brine, characterized in that: include: Step S1, first adsorption stage: Step S1-1, pumping the chloride-type low-lithium brine into a first adsorption column to perform a first adsorption to obtain a second adsorption column; Step S1-2, using water as a first priming liquid to perform a first priming on the second adsorption column to obtain a first waste liquid and a third adsorption column; Step S1-3, using water as the first desorption liquid, sequentially performing a first desorption, a second desorption and a third desorption on the third adsorption column to obtain a fourth adsorption column; wherein the first desorption, the second desorption and the third desorption respectively obtain a first purified liquid, a second purified liquid and a third purified liquid; Step S1-4, pumping the fresh chloride-type low-lithium brine into the fourth adsorption column for replacement to obtain a fifth adsorption column; Step S2, the second adsorption stage: Step S2-1, using the first purified liquid, the second purified liquid and the third purified liquid as a second top-loading liquid to perform a second top-loading on the fifth adsorption column to obtain a second waste liquid and a sixth adsorption column; Step S2-2, using water as the second analytical solution, sequentially performing a fourth desorption, a fifth desorption and a sixth desorption on the sixth adsorption column; wherein the fourth desorption, the fifth desorption and the sixth desorption respectively obtain a fourth purified liquid, a fifth purified liquid and a sixth purified liquid, and the fourth purified liquid, the fifth purified liquid and the sixth purified liquid are mixed to obtain an adsorption purified liquid; Step S3, performing reverse osmosis concentration on the adsorbed purified liquid to obtain a concentrated liquid; Step S4, the concentrated solution is sequentially extracted and stripped to obtain a lithium-containing solution; Step S5, the lithium-containing solution is post-treated to obtain the lithium-containing compound.

2. The method for producing lithium-containing compounds using chloride-type low-lithium brine according to claim 1, characterized in that: In the chloride-type low-lithium brine, the lithium ion concentration is 60 mg / L to 900 mg / L, the sodium ion concentration is 1000 mg / L to 90000 mg / L, the potassium ion concentration is 1000 mg / L to 18000 mg / L, and the magnesium ion concentration is 40000 mg / L to 120000 mg / L; Preferably, in step S1-1, the chloride-type low-lithium brine is pumped into the first adsorption column at a flow rate of 10 Bv / h to 12 Bv / h; and / or, the first adsorption time is 12±2 min.

3. The method for producing lithium-containing compounds using chloride-type low-lithium brine according to claim 1 or 2, characterized in that: In step S1-3, during the first desorption, the second desorption and the third desorption, the pumping flow rate of the first desorption liquid is independently 3.5 Bv / h to 5.0 Bv / h, and the temperature is independently 35° C. to 40° C.; Preferably, the time of the first desorption, the second desorption and the third desorption is independently 12±2 min; More preferably, in the first purified solution, the lithium ion concentration is 200 mg / L to 500 mg / L, the sodium ion concentration is 30 mg / L to 100 mg / L, the potassium ion concentration is 5 mg / L to 10 mg / L, and the magnesium ion concentration is 100 mg / L to 300 mg / L; and / or, in the second purified solution, the lithium ion concentration is 300 mg / L to 700 mg / L, the sodium ion concentration is 20 mg / L to 30 mg / L, the potassium ion concentration is 5 mg / L to 15 mg / L, and the magnesium ion concentration is 150 mg / L to 300 mg / L; and / or, in the third purified solution, the lithium ion concentration is 400 mg / L to 700 mg / L, the sodium ion concentration is 20 mg / L to 30 mg / L, the potassium ion concentration is 5 mg / L to 15 mg / L, and the magnesium ion concentration is 100 mg / L to 300 mg / L.

4. The method for producing lithium-containing compounds using chloride-type low-lithium brine according to any one of claims 1 to 3, characterized in that: In step S1-4, the replacement includes: pumping the chloride-type low-lithium brine into the fourth adsorption column at a flow rate of 1Bv / h to 2Bv / h for a first replacement; pumping the chloride-type low-lithium brine into the fourth adsorption column again at a flow rate of 11Bv / h to 12Bv / h for a second replacement; Preferably, the time for the first replacement and the second replacement is independently 12±2 min.

5. The method for producing lithium-containing compounds using chloride-type low-lithium brine according to any one of claims 1 to 4, characterized in that: Step S2-1 further includes: mixing the first purified liquid, the second purified liquid and the third purified liquid in a volume ratio of (4-5):1:1 to obtain a mixed purified liquid, and using the mixed purified liquid as the second top feed liquid; Preferably, the pumping flow rate of the second top feed liquid is 6 Bv / h to 8 Bv / h; More preferably, the second loading time is 12±2 min.

6. The method for producing lithium-containing compounds using chloride-type low-lithium brine according to any one of claims 1 to 5, characterized in that: In step S2-2, during the fourth desorption, the fifth desorption and the sixth desorption, the pumping flow rate of the second desorption liquid is independently 3.5 Bv / h to 5.0 Bv / h, and the temperature is independently 40±2° C.; Preferably, the time of the fourth desorption, the fifth desorption and the sixth desorption is independently 12±2 min; More preferably, in the fourth purified solution, the lithium ion concentration is 400 mg / L to 1700 mg / L, the sodium ion concentration is 100 mg / L to 200 mg / L, the potassium ion concentration is 15 mg / L to 40 mg / L, and the magnesium ion concentration is 500 mg / L to 800 mg / L; and / or, in the fifth purified solution, the lithium ion concentration is 500 mg / L to 700 mg / L, the sodium ion concentration is 20 mg / L to 70 mg / L, the potassium ion concentration is 5 mg / L to 15 mg / L, and the magnesium ion concentration is 150 mg / L to 300 mg / L; and / or, in the sixth purified solution, the lithium ion concentration is 700 mg / L to 800 mg / L, the sodium ion concentration is 20 mg / L to 70 mg / L, the potassium ion concentration is 5 mg / L to 15 mg / L, and the magnesium ion concentration is 150 mg / L to 300 mg / L.

7. The method for producing lithium-containing compounds using chloride-type low-lithium brine according to any one of claims 1 to 6, characterized in that: In step S3, the pressure of the reverse osmosis concentration is 3.5 MPa to 4.5 MPa.

8. The method for producing lithium-containing compounds using chloride-type low-lithium brine according to any one of claims 1 to 7, characterized in that: Step S4 comprises: adjusting the pH value of the concentrated solution to 12-13 and filtering to obtain a filtrate, and then sequentially subjecting the filtrate to the extraction and the back extraction to obtain the lithium-containing solution.

9. The method for producing lithium-containing compounds using chloride-type low-lithium brine according to claim 8, characterized in that: During the extraction process, the weight ratio of the filtrate to the extractant is (3-4):1; and / or, during the stripping process, the stripping agent used is one of carbon dioxide, hydrochloric acid solution and phosphoric acid solution.

10. The method for producing lithium-containing compounds using chloride-type low-lithium brine according to claim 8 or 9, characterized in that: The stripping agent is the carbon dioxide, and the post-treatment in step S5 is heating filtration; and / or, the stripping agent is the hydrochloric acid solution or the phosphoric acid solution, and the post-treatment in step S5 is evaporation crystallization.

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