Lithium extraction system and lithium extraction method

Abstract

A lithium extraction system and a lithium extraction method. The lithium extraction system comprises an exchange column and a liquid circulation device. The liquid circulation device has a first position, a second position, and a third position. The exchange column at the first position is used for receiving brine and adsorbing lithium ions in the brine. The exchange column at the second position is used for receiving a first residual liquid, the exchange column at the second position moves from the first position, the first residual liquid comprises a liquid that does not meet standards and is generated by the exchange column at the third position, and the first residual liquid is used for cleaning the exchange column at the second position. The exchange column at the first position is also used for receiving a second residual liquid, and the second residual liquid comprises a leaching liquid flowing out after the exchange column at the second position is cleaned. The exchange column at the third position is used for receiving a desorption liquid to desorb the lithium ions, and the exchange column at the third position moves from the second position.

Description

Lithium extraction system and lithium extraction method

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 28, 2023, with application number 202311291237.5 and application name “Lithium Extraction System and Method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of lithium production, and in particular to a lithium extraction system and a lithium extraction method. Background Art

[0003] Traditional lithium extraction methods include precipitation, carbonization, solvent extraction, and calcination. These methods not only require large footprints, consume high energy, and have low yields, but are also difficult to extract from brines with high magnesium-to-lithium ratios. The majority of existing lithium resources are stored in salt lake brines, most of which have high magnesium-to-lithium ratios. Therefore, extracting lithium from these brines has become a key focus of lithium resource development.

[0004] The recently developed adsorption method has gained widespread favor due to its advantages, including good lithium ion selectivity, simple process, and ability to extract lithium from salt lake brines with high magnesium-to-lithium ratios. However, existing adsorption lithium extraction systems suffer from low adsorption efficiency (only about 60%), low lithium yield (only about 45%), complex processes, high water consumption, and low or no production in winter.

[0005] Summary of the Invention

[0006] The present application provides a lithium extraction system and a lithium extraction method, aiming to solve the problem of low lithium ion production capacity.

[0007] To solve the above technical problems, this application provides the following technical solutions.

[0008] In a first aspect, the present application provides a lithium extraction system. The lithium extraction system includes an exchange column and a liquid circulation device; the liquid circulation device has a first position, a second position, and a third position; the exchange column at the first position is used to receive brine and adsorb lithium ions in the brine; the exchange column at the second position is used to receive a first residual liquid, the exchange column at the second position is moved from the first position, the first residual liquid includes unqualified liquid generated by the exchange column at the third position, and the first residual liquid is used to clean the exchange column at the second position; the exchange column at the first position is also used to receive a second residual liquid, and the second residual liquid includes eluent flowing out after the exchange column at the second position is cleaned; the exchange column at the third position is used to receive an analytical solution to desorb lithium ions, and the exchange column at the third position is moved from the second position.

[0009] In some embodiments, the liquid circulation device further has a fourth position, and the exchange column circulates among the first position, the second position, the third position, and the fourth position in sequence; the exchange column at the fourth position is used to receive the residual liquid after the exchange column at the first position adsorbs lithium ions, and the residual liquid is used to push out the recovered water in the exchange column at the fourth position, and the exchange column at the fourth position moves from the third position.

[0010] In some embodiments, the liquid circulation device has multiple first positions, at least one second position, at least one third position, and at least one fourth position. The exchange column passes through the multiple first positions in sequence, and then passes through the at least one second position, the at least one third position, and the at least one fourth position in sequence.

[0011] In some implementations, the total number of the first position, the second position, the third position, and the fourth position is in the range of 20-50.

[0012] In some embodiments, the multiple first positions include a first sub-position, a second sub-position, and a third sub-position; the exchange column at the first sub-position is used to receive primary brine and adsorb lithium ions in the primary brine; the exchange column at the second sub-position is used to receive secondary brine and adsorb lithium ions in the secondary brine, wherein the secondary brine is the residual liquid after the exchange column at the first sub-position adsorbs lithium ions; and the exchange column at the third sub-position is used to receive tertiary brine and adsorb lithium ions in the tertiary brine, wherein the tertiary brine is the residual liquid after the exchange column at the second sub-position adsorbs lithium ions.

[0013] In some embodiments, the first sub-position, the second sub-position, and the third sub-position are all multiple and the number is the same; any first sub-position corresponds to and is connected to one second sub-position and one third sub-position.

[0014] In some embodiments, the lithium extraction system further includes a working surface, and the exchange column has a lower end close to the working surface and an upper end away from the working surface; for the exchange column at the first sub-position, the primary brine is introduced from its upper end, and the residual liquid after adsorption flows out from its lower end; for the exchange column at the second sub-position, the secondary brine is introduced from its upper end, and the residual liquid after adsorption of lithium ions flows out from its lower end; for the exchange column at the third sub-position, the tertiary brine is introduced from its upper end, and the residual liquid after adsorption of lithium ions flows out from its lower end.

[0015] In some embodiments, the at least one second position includes a plurality of second positions, and for the exchange column at each of the plurality of second positions, the first residual liquid is introduced from the upper end thereof, and the washed residual liquid flows out from the lower end thereof.

[0016] In some embodiments, the exchange column at the second position is further configured to receive a third residual liquid, wherein the third residual liquid comprises recycled water discharged at the fourth position.

[0017] In some embodiments, the at least one third position includes multiple third positions. For the exchange column at each third position among the multiple third positions, the analytical liquid is introduced from its upper end, and the residual liquid after cleaning flows out from its lower end, and the outflowing liquid includes the unqualified liquid and the qualified liquid.

[0018] In some embodiments, the lithium extraction system includes a plurality of exchange columns, and the movement interval time between any two adjacent exchange columns is in the range of 8 minutes to 30 minutes.

[0019] In some embodiments, the flow rate of the brine at the first position is in the range of 3 BV / h to 10 BV / h.

[0020] In some embodiments, the flow rate of the first residual liquid at the second position is in the range of 2 BV / h to 10 BV / h.

[0021] In some embodiments, the flow rate of the analytical solution at the third position is in the range of 6 BV / h to 20 BV / h.

[0022] In some embodiments, the flow rate of the residual liquid after the exchange column adsorbs lithium ions at the first position at the fourth position is in the range of 1 BV / h to 6 BV / h.

[0023] In a second aspect, the present application provides a lithium extraction method. The lithium extraction method includes: an exchange column at a first position of a liquid circulation device receives brine and adsorbs lithium ions in the brine; an exchange column at a second position of the liquid circulation device receives a first residual liquid, wherein the exchange column at the second position is moved from the first position; the first residual liquid includes unqualified liquid generated by an exchange column at a third position of the liquid circulation device, and the first residual liquid is used to clean the exchange column at the second position; the exchange column at the first position receives a second residual liquid, wherein the second residual liquid includes eluent flowing out after cleaning the exchange column at the second position; and the exchange column at the third position receives an analytical solution to desorb lithium ions, wherein the exchange column at the third position is moved from the second position.

[0024] The lithium extraction system provided herein utilizes a liquid circulation device and an exchange column. The liquid circulation device delivers lithium-ion-containing brine, a desorption solution, and recycled water to the exchange column. The exchange column then absorbs and cleans the lithium ions, followed by desorption, completing the lithium ion extraction process. During this process, unqualified liquid generated at the third location can be returned to the second location for use as a cleaning solution for the exchange column. This not only reduces water consumption in production but also inhibits lithium ion loss from the exchange column during the elution process through the lithium ions in the unqualified liquid and recycled water, ensuring that the lithium adsorption capacity of the exchange column does not significantly change during the elution process. This increases the subsequent desorption of lithium ions and thus improves lithium production capacity. Furthermore, the second residual liquid after cleaning is returned to the first location for reuse, further reducing lithium loss and brine usage. It also dilutes the brine, lowering its viscosity and saturation, reducing brine crystallization in the equipment pipeline, and lowering pump pressure, thereby minimizing flow fluctuations caused by excessive pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the implementation methods or the description of the prior art. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] FIG1 is a schematic structural diagram of a lithium extraction system according to an embodiment of the present application. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0028] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be an intermediate component. When a component is referred to as being "connected to" another component, it may be directly connected to the other component or there may be an intermediate component.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification are intended only to describe specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0031] The present application provides a lithium extraction system, specifically a system for extracting lithium from a salt lake. The lithium extraction system includes an exchange column and a liquid circulation device. The liquid circulation device has a first position, a second position, and a third position. The exchange column at the first position is used to receive brine and adsorb lithium ions in the brine. The exchange column at the second position is used to receive a first residual liquid, and the exchange column at the second position is moved from the first position. The first residual liquid includes unqualified liquid produced by the exchange column at the third position, and the first residual liquid is used to clean the exchange column at the second position. The exchange column at the first position is also used to receive a second residual liquid, and the second residual liquid includes a washing liquid flowing out after the exchange column at the second position is cleaned. The exchange column at the third position is used to receive an analytical liquid to desorb lithium ions, and the exchange column at the third position is moved from the second position.

[0032] Specifically, the liquid circulation device can be an automated device, and the exchange column is arranged on the liquid circulation device and can move on the liquid circulation device. Specifically, the exchange column can move to a first position, a second position, and a third position of the liquid circulation device.

[0033] Furthermore, brine is a liquid mixed with lithium ions, and brine is passed from a brine storage tank into the lithium extraction system, thereby enabling the system to extract lithium ions from the brine. In some embodiments, the exchange column in the first position can be used to receive brine, or to receive a mixture of brine and eluent.

[0034] In some embodiments, the liquid circulation device may be provided with a liquid outlet and a liquid inlet at the first position. The exchange column moved to the first position is positioned precisely between the liquid outlet and the liquid inlet. Brine flows from the liquid outlet, passes through the exchange column in the first position, and then flows back into the liquid circulation device through the liquid inlet. During this process, the exchange column in the first position receives brine and adsorbs lithium ions therein.

[0035] In some embodiments, the liquid circulation device may also be provided with a liquid outlet and a liquid inlet in the second position. The exchange column moved to the second position is positioned precisely between the liquid outlet and the liquid inlet. The first residual liquid flows out of the liquid outlet, passes through the exchange column in the second position, and then flows back into the liquid circulation device through the liquid inlet. During this process, the first residual liquid cleans the exchange column in the second position.

[0036] In some embodiments, the liquid circulation device may also be provided with a liquid outlet and a liquid inlet at the third position. The exchange column moved to the third position is positioned precisely between the liquid outlet and the liquid inlet. The desorption liquid flows from the liquid outlet, passes through the exchange column at the third position, and then flows back into the liquid circulation device through the liquid inlet. During this process, the desorption liquid desorbs lithium ions from the exchange column at the third position.

[0037] The lithium extraction system provided by the present application includes a liquid circulation device and an exchange column. The liquid circulation device transports brine containing lithium ions to the exchange column, and the exchange column adsorbs and desorbs lithium ions to complete the extraction of lithium ions. During the extraction of lithium ions, the unqualified liquid in the third position can also be returned to the second position to be used as a cleaning liquid for the exchange column. This not only reduces the water consumption in production, but also suppresses the loss of lithium ions on the exchange column during the elution process through the lithium ions in the first residual liquid, ensuring that the lithium adsorption capacity of the exchange column does not change significantly due to the elution of the exchange column, thereby increasing the content of subsequent desorbed lithium ions and thus increasing lithium production capacity. In addition, the second residual liquid after cleaning is also returned to the first position for reuse, which not only further reduces lithium loss and reduces the amount of brine used, but also dilutes the brine, reduces the viscosity and saturation of the brine, reduces the crystallization of brine in the equipment pipeline, reduces the pressure of the pump, and reduces the flow fluctuation caused by excessive pressure.

[0038] In some embodiments, the liquid circulation device further comprises a fourth position, wherein the exchange columns cyclically move among the first position, the second position, the third position, and the fourth position. The exchange columns in the fourth position are used to receive residual liquid after the exchange columns in the first position adsorb lithium ions, and the exchange columns in the fourth position are moved from the third position. The residual liquid is used to push out the recovered water in the exchange columns in the fourth position.

[0039] In some embodiments, the liquid circulation device may also be provided with a liquid outlet and a liquid inlet in the fourth position. The exchange column moved to the fourth position is positioned exactly between the liquid outlet and the liquid inlet. The first residual liquid flows out of the liquid outlet, passes through the exchange column in the fourth position, and then flows back into the liquid circulation device through the liquid inlet.

[0040] It is understandable that since the exchange column at the fourth position is moved from the third position, there are no lithium ions (or only a very small amount of residual lithium ions) in the exchange column at the fourth position. Therefore, after the first residual liquid flows into and out of the exchange column at the fourth position, the composition of the liquid changes very little.

[0041] In some embodiments, the lithium extraction system includes four process zones, namely, an adsorption zone, a leaching zone, a desorption zone, and a recovery zone (brine top water zone). The adsorption zone corresponds to the first position, the leaching zone corresponds to the second position, the desorption zone corresponds to the third position, and the recovery zone corresponds to the fourth position.

[0042] In some embodiments, the liquid circulation device has a plurality of first positions, at least one second position, at least one third position, and at least one fourth position. The exchange column sequentially passes through the plurality of first positions and then sequentially passes through the second position, the third position, and the fourth position.

[0043] In some embodiments, the total number of the first position, the second position, the third position, and the fourth position is in the range of 20 to 50, and the number of exchange columns is also in the range of 20 to 50. For example, the total number of the first position, the second position, the third position, and the fourth position is 20, 25, 30, 35, 40, 45, or 50. It will be appreciated that the number of exchange columns may be the same as or different from the total number of the first position, the second position, the third position, and the fourth position.

[0044] For example, as shown in Figure 1, the liquid circulation system has a total of thirty locations for exchange columns. The first location has fifteen (A1 to O1), the second location has four (A2 to D2), the third location has ten (A3 to J3), and the fourth location has one (A4). Initially, columns 15 through 1 are installed in A1 to O1, columns 30 through 27 are installed in A2 to D2, columns 26 through 17 are installed in A3 to J3, and column 16 is installed in A4.

[0045] The columns then begin to move: column 15 at A1 moves to B1, and column 14 at B1 moves to C1. This continues until column 2 at N1 moves to O1. Then, column 1 at O1 moves to A2; column 27 at D2 moves to A3; column 17 at J3 moves to A4; and column 16 at A4 moves to A1. This completes the cyclic movement of the columns.

[0046] The lithium extraction system provided in the present application adopts a thirty-column continuous exchange process. By setting up four process zones, namely, an adsorption zone, a leaching zone, a desorption zone, and a recovery zone (brine top water zone), and setting up thirty exchange columns for circular movement, each exchange column can pass through the adsorption zone, the leaching zone, the desorption zone, and the recovery zone (brine top water zone), and then re-enter the adsorption zone to complete a cycle, thereby continuously producing qualified lithium liquid with a magnesium-lithium ratio of less than 3 and a lithium content higher than 500 ppm.

[0047] In some embodiments, there are multiple exchange columns, and the movement interval between any two adjacent exchange columns is 8 minutes to 30 minutes. It will be appreciated that the multiple exchange columns all move at the same speed to ensure that there is no interference between adjacent exchange columns. In some embodiments, the movement time of the exchange columns can be set based on the lithium content of the brine.

[0048] Exemplarily, there are multiple exchange columns, and the movement interval time between any two adjacent exchange columns is 10 minutes to 20 minutes.

[0049] In some embodiments, the multiple first positions include a first sub-position, a second sub-position, and a third sub-position; the exchange column at the first sub-position is used to receive primary brine and adsorb lithium ions in the primary brine; the exchange column at the second sub-position is used to receive secondary brine and adsorb lithium ions in the secondary brine, wherein the secondary brine is the residual liquid after the exchange column at the first sub-position adsorbs lithium ions; the exchange column at the third sub-position is used to receive tertiary brine and adsorb lithium ions in the tertiary brine, wherein the tertiary brine is the residual liquid after the exchange column at the second sub-position adsorbs lithium ions.

[0050] In some embodiments, the first sub-position, the second sub-position, and the third sub-position are all multiple and the number is the same; any first sub-position corresponds to and is connected to one second sub-position and one third sub-position.

[0051] It is understood that, based on the above embodiment, the exchange columns in the adsorption zone can receive brine in a "five-in-parallel, three-in-series" manner. It is understood that the "five-in-parallel, three-in-series" manner means that the number of first sub-positions, second sub-positions, and third sub-positions is five; the five first sub-positions are in a parallel structure, that is, the five liquid outlets of the first sub-positions discharge liquid simultaneously and the five liquid inlets of the first sub-positions take liquid in simultaneously without interfering with each other; the five second sub-positions are in a parallel structure, that is, the five liquid outlets of the second sub-positions discharge liquid simultaneously and the five liquid inlets of the second sub-positions take liquid in simultaneously without interfering with each other; and the five third sub-positions are in a parallel structure, that is, the five liquid outlets of the third sub-positions discharge liquid simultaneously and the five liquid inlets of the third sub-positions take liquid in simultaneously without interfering with each other.

[0052] In some embodiments, as shown in FIG1 , the brine flowing into the lithium extraction system from the outside is divided into five streams (i.e., five primary brines), and the five primary brines flow into corresponding exchange columns 1 to 5 respectively, so that exchange columns 1 to 5 respectively receive a corresponding stream of primary brine and adsorb lithium ions in the primary brine.

[0053] In some embodiments, as shown in FIG1 , five streams of adsorbed secondary brine will flow out of exchange columns 1 to 5 respectively, and the five streams of secondary brine will flow into corresponding exchange columns 6 to 10 respectively, so that exchange columns 6 to 10 respectively receive a corresponding stream of secondary brine and adsorb lithium ions in the secondary brine.

[0054] In some embodiments, as shown in FIG1 , five streams of tertiary brine that have been adsorbed will flow out of the exchange columns 6 to 10 respectively, and the five streams of tertiary brine will flow into the corresponding exchange columns 11 to 15 respectively, so the exchange columns 11 to 15 respectively receive a corresponding stream of tertiary brine and adsorb the lithium ions in the tertiary brine.

[0055] Therefore, the flow paths of the five brine streams involved in the aforementioned "five in parallel and three in series" method are: O1→J1→E1, N1→I1→D1, M1→H1→C1, L1→G1→B1, and K1→F1→A1.

[0056] In other embodiments, the flow paths of the five brine streams involved in the aforementioned "five in parallel and three in series" method can also be: O1→F1→A1, N1→G1→B1, M1→H1→C1, L1→I1→D1, and K1→J1→E1.

[0057] Furthermore, based on the above embodiment, the exchange column can also be moved in the first position by rotating. Each exchange column absorbs a stream of brine corresponding to the position each time it rotates to a position. For example, when the exchange column 15 at A1 moves to B1, the exchange column 15 switches from receiving a stream of tertiary brine to receiving another stream of tertiary brine. When the exchange column 11 at E1 moves to F1, the exchange column 11 switches from receiving a stream of tertiary brine to receiving a stream of secondary brine. Similarly, when the exchange column 6 at J1 moves to K1, the exchange column 6 switches from receiving a stream of secondary brine to receiving a stream of primary brine.

[0058] Therefore, each exchange column adsorbs brine three times for the first time starting from entering A1 and continues to rotate to O1, that is, each exchange column adsorbs brine fifteen times (three times of brine, two times of brine, and one times of brine five times each).

[0059] In other embodiments, the method of "seven in parallel and two strings" or "eight in parallel and two strings" can also be adopted. Among them, "seven in parallel" and "eight in parallel" can refer to the "five in parallel" mentioned above, and "two strings" can refer to the "three strings" mentioned above, and they will not be elaborated here. It can be understood that in the thirty-column lithium extraction structure provided in the present application, when the number of the first position increases or decreases, the number of the second position, or the third position, or the fourth position can be reduced or increased accordingly. Therefore, while ensuring that the total amount of the thirty columns remains unchanged, the number of different types of positions can be adaptively adjusted.

[0060] Through the above-mentioned setting, each brine can be adsorbed by three exchange columns to ensure that the lithium ions in the brine are fully absorbed, greatly improving the lithium yield. And, understandably, the exchange column located at A1 (exchange column 15) has the strongest adsorption capacity because its front end is a desorption process and has not undergone brine adsorption. Then, as the exchange column moves, the lithium ion content in the exchange column gradually increases, and the lithium content of the exchange column on O1 is basically saturated with adsorption. And most of the residual liquid after adsorption can be discharged directly to the salt field, and a small part is used as the inlet water of the fourth position of the recovery area.

[0061] In some embodiments, the lithium extraction system includes a working surface, and the exchange column has a lower end close to the working surface and an upper end away from the working surface; for the exchange column in the first sub-position, primary brine is introduced from its upper end, and the residual liquid after adsorption flows out from its lower end; for the exchange column in the second sub-position, secondary brine is introduced from its upper end, and the residual liquid after adsorption of lithium ions flows out from its lower end; for the exchange column in the third sub-position, tertiary brine is introduced from its upper end, and the residual liquid after adsorption of lithium ions flows out from its lower end.

[0062] Specifically, the working surface can be the ground or the surface of a workbench. The exchange column can be cylindrical in structure, so the relative working surface includes two opposite ends, namely the upper end and the lower end. It can be understood that the structures of the thirty exchange columns mentioned above are all the same.

[0063] In some embodiments, based on the above embodiments, the liquid inlet method of the exchange column may not be completely the same. As shown in Figure 1, the liquid outlet and liquid inlet of the first sub-position are respectively located at the upper and lower ends of the corresponding exchange column, so the upper end of the exchange column in the first sub-position receives brine from the liquid outlet, and the lower end discharges brine to the liquid inlet. The liquid outlet and liquid inlet of the second sub-position are respectively located at the lower and upper ends of the corresponding exchange column, so the lower end of the exchange column in the second sub-position receives brine from the liquid outlet, and the upper end discharges brine to the liquid inlet. The exchange column in the third sub-position can refer to the exchange column in the first sub-position and will not be described in detail here.

[0064] In some embodiments, all exchange columns at the first position absorb lithium ions in a top-in, bottom-out (top-end in, bottom-end out) or bottom-in, top-out (bottom-end in, top-end out) manner.

[0065] In some embodiments, the exchange column at the first sub-position and the exchange column at the third sub-position absorb lithium ions in a bottom-in-top-out manner, while the exchange column at the second sub-position absorbs lithium ions in a top-in-bottom-out manner.

[0066] In some embodiments, the exchange columns at the first sub-position and the second sub-position use a top-in, bottom-out method to adsorb lithium ions, while the exchange columns at the third sub-position use a bottom-in, top-out method to adsorb lithium ions.

[0067] By adopting the top-in-bottom-out method or the combination of the top-in-bottom-out and bottom-in-top-out methods, each exchange column has the opportunity to adsorb lithium ions through the top-in-bottom-out and bottom-in-top-out methods, so that the lithium content adsorbed at the upper and lower positions of each exchange column is basically the same, that is, the lithium content near the upper end is the same as the lithium content near the lower end, and the resin can be loosened to avoid excessive pressure at the bottom of the exchange column, thereby reducing the probability of breakage and clogging of the adsorbent in the exchange column.

[0068] In some embodiments, the flow rate of the brine at the first position is 3 BV / h to 10 BV / h. Exemplarily, the flow rate of the brine at the first position is 3 BV / h to 7 BV / h.

[0069] In some embodiments, the lithium content in the brine is 100 mg / L to 1500 mg / L. Exemplarily, the lithium content in the brine is greater than 150 mg / L.

[0070] In some embodiments, the amount of lithium adsorbed by the exchange column after passing through O1 is in the range of 1 mg / g to 5 mg / g. Exemplarily, the amount of lithium adsorbed by the exchange column after passing through O1 is in the range of 2 mg / g to 4 mg / g.

[0071] In some embodiments, there are multiple second positions. For the exchange column at the second position, the first residual liquid is introduced from the upper end thereof, and the residual liquid after washing flows out from the lower end thereof.

[0072] Specifically, the exchange column at the second position can adopt a top-in, bottom-out liquid inlet method. As shown in Figure 1, the number of second positions can be four. The initial liquid inlet position of the first residual liquid is at D2.

[0073] Therefore, the flow mode of the first residual liquid at multiple second positions is: entering the upper end of the corresponding exchange column from the liquid outlet at D2, and flowing out from the lower end of the exchange column to the liquid outlet at D2; then, entering the upper end of the corresponding exchange column through the liquid outlet at C2, and flowing out from the lower end of the exchange column to the liquid outlet at C2. The first residual liquid flows in this way in sequence until it flows to A1 to complete the elution process of the elution zone.

[0074] When the exchange column at O1 moves to A2 (as shown in Figure 1, exchange column 1 moves to A2), the exchange column that moves to A2 actually washes the residual liquid from the previous position (B2). In addition, the secondary residual liquid flowing out of A2 can also flow back to the brine buffer tank and mix with the brine to re-enter the adsorption zone (i.e., the secondary residual liquid mixes with the primary brine).

[0075] Because the first residual liquid contains a high lithium content, the benefits of setting up a second position not only reduce lithium loss and brine usage, but also dilute the brine, reducing its viscosity and saturation, reducing brine crystallization in the equipment pipeline, and lowering pump pressure, thereby reducing flow fluctuations caused by excessive pressure. In addition, after eluting in four second positions, the exchange column is gradually rinsed clean, removing most impurity ions.

[0076] In some embodiments, the flow rate of the first residual liquid at the second position is 2 BV / h to 10 BV / h. Exemplarily, the flow rate of the first residual liquid at the second position is 4 BV / h to 8 BV / h.

[0077] In some embodiments, the lithium content in the first residual solution is in the range of 100 ppm to 600 ppm. For example, the lithium content in the first residual solution is in the range of 200 ppm to 500 ppm.

[0078] In some embodiments, the magnesium-to-lithium ratio in the first residual solution is less than 3:1, and the magnesium content is in the range of 50 mg / L to 1000 mg / L. Exemplarily, the magnesium-to-lithium ratio is less than 2:1, and the magnesium content is in the range of 50 mg / L to 500 mg / L.

[0079] In some embodiments, the total amount of liquid introduced into the second position is 3BV to 6BV. Exemplarily, the total amount of liquid introduced into the second position is 4BV to 5BV.

[0080] In some embodiments, the exchange column in the second position is further configured to receive a third residual liquid, which comprises a portion of the residual liquid remaining after lithium ions are desorbed from the exchange column in the third position. It is understood that the second position receives the unqualified liquid (the third residual liquid) after desorption, as well as the first residual liquid. Using these two streams of recycled water instead of pure water or tap water for washing can significantly reduce production water usage. Furthermore, the lithium ions contained in the recycled water can inhibit lithium ion loss from the adsorbent during the elution process, ensuring that the lithium adsorption capacity of the adsorbent on the exchange column does not change significantly during the elution process, thereby increasing the lithium ion content of the subsequent desorption liquid and improving lithium production capacity.

[0081] In some embodiments, there are multiple third positions. For the exchange column at the third position, the analytical solution is introduced from the upper end, and the residual liquid after cleaning flows out from the lower end, and the outflowing liquid includes the third residual liquid and the qualified liquid.

[0082] Specifically, the exchange column at the third position can adopt a top-in, bottom-out liquid inlet method. As shown in Figure 1, the number of third positions can be ten. The initial inlet position of the analytical solution is at J3.

[0083] Therefore, the flow mode of the analytical liquid at multiple third positions is: entering the upper end of the corresponding exchange column from the liquid outlet at J3, and flowing out from the lower end of the exchange column to the liquid outlet at J3; then, entering the upper end of the corresponding exchange column through the liquid outlet at I3, and flowing out from the lower end of the exchange column to the liquid outlet at I3. The analytical liquid flows in this way in sequence until it flows to A3 to complete the desorption process in the desorption zone.

[0084] When the exchange column at D2 moves to A3 (as shown in Figure 1, the exchange column 27 moves to A3), the exchange column moved to A3 actually uses the water desorbed from the previous position (B3). In addition, the unqualified liquid (the third residual liquid) flowing out of A3 can also be collected in the second position. It can be understood that the liquid that just flows out of A3 is the rinsing water in the upper position remaining in the exchange column and some desorption water with low lithium concentration, collectively referred to as unqualified liquid (the third residual liquid). After the unqualified liquid flows out, the next thing to come out is qualified liquid, which is the target product of the continuous ion exchange system.

[0085] Optionally, the volume of the unqualified liquid is in the range of 0.5 BV to 1 BV. Exemplarily, the volume of the unqualified liquid is in the range of 0.6 BV to 0.8 BV.

[0086] In some embodiments, the flow rate of the analytical solution at the third position is 6 BV / h to 20 BV / h. Exemplarily, the flow rate of the analytical solution at the third position is 10 BV / h.

[0087] In some embodiments, the analytical solution introduced at J1 is pure water or tap water, with a conductivity of less than 200 μs / cm and a temperature range of 30° C. to 60° C. For example, the analytical solution has a conductivity of 10 μs / cm to 50 μs / cm and a temperature range of 35° C. to 45° C.

[0088] In some embodiments, there is one fourth position, and for the exchange column at the fourth position, the first residual liquid enters from the lower end and flows out from the upper end. The outflowing first residual liquid and the third residual liquid are combined and flowed into the exchange column at the second position.

[0089] Specifically, the exchange column at the fourth position can adopt a bottom-in-top-out liquid inlet method. When the exchange column at J3 moves to A4 (as shown in FIG1 , the exchange column 17 moves to A4), it enters the recovery zone (the brine top water zone).

[0090] If the top-in and bottom-out method is used, the incoming brine will easily form a coagulant layer with the water in the column, resulting in a high content of impurity ions in the recycled water, and the qualified recyclable water will be less than 0.5BV. If the bottom-in and top-out method is used, the qualified recyclable water can reach up to about 0.8BV. The adsorption tail liquid produced by the adsorption section after three-stage adsorption in the brine top water section enters the low calcium and magnesium water tank and is mixed with unqualified water to be used as the inlet water for leaching.

[0091] After the exchange column goes through the four steps above, it re-enters the adsorption stage to begin a new cycle. This process can produce qualified liquid continuously for 24 hours, ensuring the production capacity of lithium extraction.

[0092] In some embodiments, the flow rate of the first residual liquid at the fourth position is 1 BV / h to 6 BV / h. Exemplarily, the flow rate of the first residual liquid at the fourth position is 2 BV / h to 4 BV / h.

[0093] In some embodiments, the amount of water introduced into the fourth position by the first residual liquid is 0.3BV to 1BV. Exemplarily, the amount of water introduced into the fourth position by the first residual liquid is 0.5BV to 0.7BV.

[0094] In some embodiments, the present application also provides a lithium extraction method, comprising:

[0095] An exchange column at a first position of the liquid circulation device receives brine and adsorbs lithium ions in the brine;

[0096] An exchange column at a second position of the liquid circulation device receives a first residual liquid, wherein the exchange column at the second position is moved from the first position; the first residual liquid includes unqualified liquid produced by the exchange column at a third position of the liquid circulation device, and the first residual liquid is used to clean the exchange column at the second position;

[0097] The exchange column at the first position receives a second residual liquid, wherein the second residual liquid includes an eluent flowing out after the exchange column at the second position is cleaned; and

[0098] The exchange column at the third position receives an analyte solution to desorb lithium ions, wherein the exchange column at the third position is moved from the second position.

[0099] The lithium extraction method provided in this application has the following advantages: First, the continuous ion exchange process of thirty columns can fully improve the yield in details. When the lithium adsorption amount is greater than 2 mg / g, the lithium extraction rate can be as high as about 95%, and the maximum lithium adsorption amount can reach about 5 mg / g.

[0100] Second, the desorption flow rate can be adjusted within a range according to the lithium content of the adsorbed brine, achieving an average lithium desorption rate of approximately 100%, ensuring complete desorption of the adsorbed lithium. This can avoid the problem of a decrease in lithium yield and a gradual decrease in yield due to incomplete desorption, which in turn leads to a gradual increase in the lithium content of the adsorption tail liquid.

[0101] Third, this lithium extraction method utilizes a large number of exchange columns, with the number of exchange columns in the elution zone and the number of exchange columns in the desorption zone being rationally distributed and utilized. This improves production capacity, enabling the method to produce qualified solution continuously for 24 hours. The qualified solution has a lithium content exceeding 500ppm and can reach a maximum of approximately 1400mg / L.

[0102] Fourth, this lithium extraction method fully considers the reuse of water. The desorbed solution has a high lithium content, which saves more than 20% of water compared with the traditional single-tower process and the 18-column continuous desorption process, and the maximum water saving can reach about 50%.

[0103] Fifth, this lithium extraction method can utilize brine saturated with a high magnesium-to-lithium ratio (Mg / Li ratio) greater than 500. The resulting qualified solution has a low magnesium-to-lithium ratio, typically less than 2:1. This significantly reduces the amount of work and energy required for subsequent membrane refining of the qualified solution.

[0104] The technical solution of the present application will be further described below with reference to the embodiments and drawings.

[0105] Example 1

[0106] Brine 1 was used, and the composition of brine 1 is shown in Table 1. The specific operation of lithium extraction is as follows:

[0107] 1) Brine filtration: Use one or two of bag filters, backwash filters, and candle filters. The filtration accuracy is less than 25 μm, and illustratively, the filtration accuracy is within the range of 3 μm to 6 μm.

[0108] 2) Brine adsorption: Adsorption is performed using exchange columns and a liquid circulation device. The first position in the adsorption zone is 15, and a five-in-three-series process is used, employing a mixed top-in, bottom-out, and bottom-in, top-out process. The brine flow rate is 8.6 BV / h, and the exchange column rotates once every 12 minutes, moving one position. The flow paths of the five brine streams are: O1→F1→A1, N1→G1→B1, M1→H1→C1, L1→I1→D1, and K1→J1→E1. The second sub-position is bottom-in, top-out, and the remaining positions are top-in, bottom-out. The feed is a mixture of eluent and brine.

[0109] 3) Wash: The wash section has four second positions, using a top-in, bottom-out cascade process. The wash flow rate is 6 BV / h, and the total wash volume is 4.8 BV. The exchange column rotates once every 12 minutes, moving one position. The desorbed unqualified liquid (the third residual liquid) and the reflux liquid (the first residual liquid) after adsorption are introduced.

[0110] 4) Lithium desorption: The desorption zone adopts countercurrent desorption, and the water entering each exchange column is desorbed from the previous position. The volume of unqualified liquid is 0.69BV. The unqualified liquid is recovered as rinsing water and enters the low calcium and magnesium water tank for use as rinsing water. After the unqualified liquid flows out, the next to come out is qualified liquid, which is the target product of the continuous ion exchange system. The qualified liquid enters the buffer tank for collection and the lithium content and magnesium-lithium ratio are measured. After further refinement to remove impurity ions, battery-grade lithium carbonate is produced. The flow rate of the desorption section is 15.24BV / h. Pure water enters position 17 of the desorption section with a conductivity of 20us / cm and a water temperature of 40°C.

[0111] 5) Recovery: The exchange column moves from the third position to the fourth position, entering the recovery zone. There is only one fourth position. A bottom-in, top-out method is used. The flow rate of the first residual liquid (brine top water) is 2.6 BV / h. The first residual liquid volume is 0.52 BV.

[0112] Table 1

[0113] Example 2

[0114] Brine 2 was used, and its composition is shown in Table 2. The brine flow rate in the adsorption zone and the elution water flow rate in the desorption zone were changed, while the rest remained the same. The specific operation of lithium extraction is as follows:

[0115] The brine flow rate in the adsorption section and the pure water flow rate in the desorption section have changed, while the rest remain the same. The specific operations are as follows:

[0116] 1) Brine filtration: Use one or two of bag filters, backwash filters, and candle filters. The filtration accuracy is less than 25 μm, and illustratively, the filtration accuracy is within the range of 3 μm to 6 μm.

[0117] 2) Brine adsorption: Adsorption is performed using exchange columns and a liquid circulation device. The number of first positions in the adsorption zone is 15, and a five-in-three-series process is used, employing a mixed process of top-in, bottom-out, and bottom-in, top-out. The brine flow rate is 5.8 BV / h, and the exchange column rotates once every 12 minutes, moving one position. The flow paths of the five brine streams are: O1→F1→A1, N1→G1→B1, M1→H1→C1, L1→I1→D1, and K1→J1→E1. The second sub-position is bottom-in, top-out, and the remaining positions are top-in, bottom-out. The feed is a mixture of eluent and brine.

[0118] 3) Wash: The wash section has four second positions, using a top-in, bottom-out cascade process. The wash flow rate is 6 BV / h, and the total wash volume is 4.8 BV. The exchange column rotates once every 12 minutes, moving one position. The desorbed unqualified liquid (the third residual liquid) and the reflux liquid (the first residual liquid) after adsorption are introduced.

[0119] 4) Lithium desorption: The desorption zone adopts countercurrent desorption, and the water entering each exchange column is desorbed from the previous position. The volume of unqualified liquid is 0.69BV. The unqualified liquid is recovered as rinsing water and enters the low calcium and magnesium water tank for use as rinsing water. After the unqualified liquid flows out, the next to come out is qualified liquid, which is the target product of the continuous ion exchange system. The qualified liquid enters the buffer tank for collection and the lithium content and magnesium-lithium ratio are measured. After further refinement to remove impurity ions, battery-grade lithium carbonate is produced. The flow rate of the desorption section is 16.31BV / h. Pure water enters position 17 of the desorption section, with a conductivity of 20us / cm and a water temperature of 40°C.

[0120] 5) Recovery: The exchange column moves from the third position to the fourth position, entering the recovery zone. There is only one fourth position. A bottom-in, top-out method is used. The flow rate of the first residual liquid (brine top water) is 2.6 BV / h. The first residual liquid volume is 0.52 BV.

[0121] Table 2

[0122] Example 3

[0123] Brine 3 was used, and its composition is shown in Table 3. The brine flow rate in the adsorption zone and the elution water temperature in the desorption zone were changed, while the rest remained the same. The specific operation of lithium extraction is as follows:

[0124] 1) Brine filtration: Use one or two of bag filters, backwash filters, and candle filters. The filtration accuracy is less than 25 μm, and illustratively, the filtration accuracy is within the range of 3 μm to 6 μm.

[0125] 2) Brine adsorption: Adsorption is performed using exchange columns and a liquid circulation device. The first position in the adsorption zone is 15, and a five-in-three-series process is used, employing a mixed process of top-in, bottom-out, and bottom-in, top-out. The brine flow rate is 2.47 BV / h, and the exchange column rotates once every 12 minutes, moving one position. The flow paths of the five brine streams are: O1→F1→A1, N1→G1→B1, M1→H1→C1, L1→I1→D1, and K1→J1→E1. The second sub-position is bottom-in, top-out, and the remaining positions are top-in, bottom-out. The feed is a mixture of eluent and brine.

[0126] 3) Wash: The wash section has four second positions, using a top-in, bottom-out cascade process. The wash flow rate is 6 BV / h, and the total wash volume is 4.8 BV. The exchange column rotates once every 12 minutes, moving one position. The desorbed unqualified liquid (the third residual liquid) and the reflux liquid (the first residual liquid) after adsorption are introduced.

[0127] 4) Lithium desorption: The desorption zone adopts countercurrent desorption, and the water entering each exchange column is desorbed from the previous position. The volume of unqualified liquid is 0.69BV. The unqualified liquid is recovered as rinsing water and enters the low calcium and magnesium water tank for use as rinsing water. After the unqualified liquid flows out, the next to come out is qualified liquid, which is the target product of the continuous ion exchange system. The qualified liquid enters the buffer tank for collection and the lithium content and magnesium-lithium ratio are measured. After further refinement to remove impurity ions, battery-grade lithium carbonate is produced. The flow rate of the desorption section is 14.16BV / h. Pure water enters position 17 of the desorption section, with a conductivity of 20us / cm and a water temperature of 50°C.

[0128] 5) Recovery: The exchange column moves from the third position to the fourth position, entering the recovery zone. There is only one fourth position. A bottom-in, top-out method is used. The flow rate of the first residual liquid (brine top water) is 2.6 BV / h. The first residual liquid volume is 0.52 BV.

[0129] Table 3

[0130] The above Examples 1-3 were all based on the initial start-up of the equipment, and the lithium extraction process lasted for 6 hours, that is, after the exchange column had completely cycled through one process, sampling and analysis were performed. In Examples 1-3, qualified liquid was taken after 24 hours of circulation and ion content analysis was performed using an ICP device.

[0131] Adsorption extraction rate = (1- adsorption tail liquid lithium ion content / brine lithium content) * 100%

[0132] Desorption rate = (qualified liquid lithium content * qualified liquid volume) / (brine lithium content * total brine volume * adsorption extraction rate) * 100%

[0133] The analysis results are shown in Table 4 below:

[0134] Table 4

[0135] From the above test results, it can be seen that the qualified liquid produced by this process has a high extraction rate at room temperature. If the lithium concentration of the brine is increased, the extraction rate will be above 90%. The desorption rate in the desorption zone is around 100%, achieving the effect of complete desorption. The qualified liquid product obtained by this process has a relatively low magnesium-lithium ratio, which can be reduced from over 500 to below 2. This lays a solid foundation for the precipitation of qualified battery-grade lithium carbonate. This process requires approximately 300-500 tons of pure water per ton of lithium carbonate, which is more than 20% lower than the external conventional continuous desorption process of around 600.

[0136] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", and "outside" are based on the orientation or positional relationship described in the accompanying drawings. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present application.

[0137] The above disclosure is only a preferred embodiment of the present application, and certainly cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present application are still within the scope covered by the present application.

Claims

1. A lithium extraction system, characterized in that: It includes an exchange column and a liquid circulation device; the liquid circulation device has a first position, a second position, and a third position; The exchange column at the first position is used to receive brine and adsorb lithium ions in the brine; The exchange column at the second position is used to receive a first residual liquid, the exchange column at the second position is moved from the first position, the first residual liquid includes unqualified liquid generated by the exchange column at the third position, and the first residual liquid is used to clean the exchange column at the second position; The exchange column at the first position is also used to receive a second residual liquid, and the second residual liquid includes a washing liquid flowing out after the exchange column at the second position is cleaned; as well as The exchange column at the third position is used to receive the analytical solution to desorb lithium ions, and the exchange column at the third position is moved from the second position.

2. The lithium extraction system according to claim 1, characterized in that: The liquid circulation device also has a fourth position, and the exchange column circulates and moves among the first position, the second position, the third position, and the fourth position in sequence; the exchange column at the fourth position is used to receive the residual liquid after the exchange column at the first position adsorbs lithium ions, and the residual liquid is used to push out the recovered water in the exchange column at the fourth position, and the exchange column at the fourth position moves from the third position.

3. The lithium extraction system according to claim 2, characterized in that: The liquid circulation device has a plurality of first positions, at least one second position, at least one third position, and at least one fourth position. The exchange column passes through the plurality of first positions in sequence, and then passes through the at least one second position, the at least one third position, and the at least one fourth position in sequence.

4. The lithium extraction system according to claim 3, characterized in that: A total number of the first position, the second position, the third position, and the fourth position is in the range of 20 to 50.

5. The lithium extraction system according to claim 3, characterized in that: The plurality of first positions include a first sub-position, a second sub-position, and a third sub-position; The exchange column at the first sub-position is used to receive the primary brine and adsorb the lithium ions in the primary brine; The exchange column at the second sub-position is used to receive secondary brine and adsorb lithium ions in the secondary brine, wherein the secondary brine is the residual liquid after the exchange column at the first sub-position adsorbs lithium ions; and The exchange column at the third sub-position is used to receive tertiary brine and adsorb lithium ions in the tertiary brine, wherein the tertiary brine is the residual liquid after the exchange column at the second sub-position adsorbs lithium ions.

6. The lithium extraction system according to claim 5, characterized in that: The first sub-position, the second sub-position, and the third sub-position are all multiple and the number is the same; any first sub-position corresponds to and is connected to a second sub-position and a third sub-position.

7. The lithium extraction system according to claim 6, characterized in that: The lithium extraction system further comprises a working surface, and the exchange column has a lower end close to the working surface and an upper end away from the working surface; For the exchange column at the first sub-position, the primary brine is introduced from the upper end thereof, and the residual liquid after adsorption flows out from the lower end thereof; For the exchange column at the second sub-position, the secondary brine is introduced from the upper end thereof, and the residual liquid after adsorbing lithium ions flows out from the lower end thereof; and For the exchange column at the third sub-position, the tertiary brine is introduced from the upper end thereof, and the residual liquid after adsorbing lithium ions flows out from the lower end thereof.

8. The lithium extraction system according to claim 7, characterized in that: The at least one second position includes a plurality of second positions. For the exchange column in each of the plurality of second positions, the first residual liquid is introduced from the upper end thereof, and the residual liquid after washing flows out from the lower end thereof.

9. The lithium extraction system according to claim 1, characterized in that: The exchange column at the second position is further used to receive a third residual liquid, wherein the third residual liquid includes recovered water discharged at the fourth position.

10. The lithium extraction system according to claim 8, characterized in that: The at least one third position includes a plurality of third positions. For the exchange column at each third position among the plurality of third positions, the analytical liquid is introduced from the upper end thereof, and the residual liquid after washing flows out from the lower end thereof, and the liquid flowing out includes the third residual liquid and qualified liquid.

11. The lithium extraction system according to claim 2, characterized in that: The lithium extraction system comprises a plurality of exchange columns, and the moving interval time between any two adjacent exchange columns is within the range of 8 minutes to 30 minutes.

12. The lithium extraction system according to claim 1, characterized in that: The flow rate of the brine at the first position is in the range of 3 BV / h to 10 BV / h.

13. The lithium extraction system according to claim 1, characterized in that: The flow rate of the first residual liquid at the second position is in the range of 2 BV / h to 10 BV / h.

14. The lithium extraction system according to claim 1, characterized in that: The flow rate of the analytical solution at the third position is in the range of 6 BV / h to 20 BV / h.

15. The lithium extraction system according to claim 2, characterized in that: The flow rate of the residual liquid after the exchange column adsorbs lithium ions at the first position at the fourth position is in the range of 1 BV / h to 6 BV / h.

16. A method for extracting lithium, characterized in that: include: An exchange column at a first position of the liquid circulation device receives brine and adsorbs lithium ions in the brine; The exchange column at the second position of the liquid circulation device receives a first residual liquid, wherein the exchange column at the second position is moved from the first position; the first residual liquid includes unqualified liquid produced by the exchange column at the third position of the liquid circulation device, and the first residual liquid is used to clean the exchange column at the second position; The exchange column at the first position receives a second residual liquid, wherein the second residual liquid includes a washing liquid flowing out after the exchange column at the second position is cleaned; and The exchange column at the third position receives the analytical solution to desorb lithium ions, wherein the exchange column at the third position Moved from the second position.

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