Lithium extraction system and method

Abstract

A lithium extraction system and 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 arranged at the first position is used to receive brine and adsorb lithium ions in the brine; the exchange column arranged at the second position is used to receive a first residual liquid, the first residual liquid comprises unqualified liquid produced by the exchange column at the third position; the exchange column at the second position is moved from the first position, the first residual liquid is used to clean the exchange column at the second position; the exchange column arranged at the first position is also used to receive a second residual liquid, the second residual liquid comprises a washing liquid flowing out after the exchange column at the second position is cleaned; the exchange column arranged at the third position is used to receive an analytical liquid to desorb lithium ions, the exchange column at the third position is moved from the second position. The lithium extraction system can solve the problem of low lithium ion production capacity.

Description

Technical Field

[0001] The present application relates to the technical field of lithium extraction, and in particular to a lithium extraction system and method. Background Art

[0002] Traditional lithium extraction methods mainly include precipitation, carbonization, solvent extraction, calcination, etc. In addition to the problems of large footprint, high energy consumption and low yield, it is also difficult to extract lithium from high magnesium-lithium ratio brine. Most of the existing lithium resources are stored in salt lake brine, most of which are high magnesium-lithium ratio brines. Therefore, lithium extraction from high magnesium-lithium ratio brines has become the focus of lithium resource development.

[0003] The adsorption method developed in recent years has been widely favored due to its advantages of good selectivity for lithium ions, simple process, and ability to extract lithium from brine in salt lakes with a high magnesium-to-lithium ratio. However, the current lithium extraction system using the adsorption method has problems such as low adsorption efficiency (only about 60%), low lithium yield (only about 45%), complex process, high water consumption, and low or no production in winter. Summary of the invention

[0004] The purpose of this application is to provide a lithium extraction system and method to solve the problem of low lithium ion production capacity.

[0005] To achieve the purpose of this application, this application provides the following technical solutions:

[0006] In a first aspect, the present application provides a lithium extraction system, comprising 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 arranged at the first position is used to receive brine and adsorb lithium ions in the brine; the exchange column arranged at the second position is used to receive a first residual liquid, which includes unqualified liquid produced by the exchange column at the third position; the exchange column at the second position is moved from the first position, and the first residual liquid is used to clean the exchange column at the second position; the exchange column arranged at the first position is also used to receive a second residual liquid, which includes a washing liquid flowing out after the exchange column at the second position is cleaned; the exchange column arranged 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.

[0007] In one embodiment, the liquid circulation device further 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 arranged 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.

[0008] In one embodiment, the liquid circulation device has a plurality of the first positions, and at least one of the second positions, and at least one of the third positions, and at least one of the fourth positions. The exchange column passes through a plurality of the first positions in sequence, and then passes through the second positions, the third positions, and the fourth positions in sequence.

[0009] In one implementation manner, the total number of the first position, the second position, the third position and the fourth position is 20 to 50.

[0010] In one embodiment, the multiple first positions include a first sub-position, a second sub-position and a third sub-position; the exchange column arranged at the first sub-position is used to receive primary brine and adsorb lithium ions in the primary brine; the exchange column arranged at the second sub-position is used to receive secondary brine and adsorb lithium ions in the secondary brine; the secondary brine is the residual liquid after the exchange column at the first sub-position adsorbs lithium ions; the exchange column arranged at the third sub-position is used to receive tertiary brine and adsorb lithium ions in the tertiary brine; the tertiary brine is the residual liquid after the exchange column at the second sub-position adsorbs lithium ions.

[0011] In one embodiment, 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 has a corresponding connected second sub-position and a third sub-position.

[0012] In one embodiment, the lithium extraction system includes a working surface, and the exchange column includes a lower end close to the working surface and an upper end away from the working surface; for the exchange column arranged at the first sub-position, the primary brine is introduced from the upper end, and the residual liquid after adsorption flows out from the lower end; for the exchange column arranged at the second sub-position, the secondary brine is introduced from the upper end, and the residual liquid after adsorption of lithium ions flows out from the lower end; for the exchange column arranged at the third sub-position, the tertiary brine is introduced from the upper end, and the residual liquid after adsorption of lithium ions flows out from the lower end.

[0013] In one embodiment, there are multiple second positions, and the first residual liquid is introduced into the exchange column arranged at the second position from the upper end, and the residual liquid after washing flows out from the lower end.

[0014] In one embodiment, the exchange column disposed at the second position is also used to receive a third residual liquid, and the third residual liquid includes the recycled water discharged from the fourth position.

[0015] In one embodiment, there are multiple third positions, and the exchange columns are arranged at the third positions. The analytical liquid is introduced from the upper end, and the residual liquid after cleaning flows out from the lower end, and the outflowing liquid includes the unqualified liquid and the qualified liquid.

[0016] In one embodiment, there are multiple exchange columns, and the movement interval between two adjacent exchange columns is 8 minutes to 30 minutes.

[0017] In one embodiment, the flow rate of the brine at the first position is 3 BV / h to 10 BV / h.

[0018] In one embodiment, the flow rate of the first residual liquid at the second position is 2 BV / h to 10 BV / h.

[0019] In one embodiment, the flow rate of the analytical solution at the third position is 6 BV / h to 20 BV / h.

[0020] In one embodiment, the flow rate of the residual liquid after the exchange column at the first position adsorbs lithium ions at the fourth position is 1 BV / h to 6 BV / h.

[0021] In a second aspect, the present application provides a lithium extraction method, comprising: an exchange column at a first position receives brine and adsorbs lithium ions in the brine; an exchange column at a second position receives a first residual liquid, the first residual liquid includes unqualified liquid produced by the exchange column at the third position; the exchange column at the second position is moved from the first position, the first residual liquid is used to clean the exchange column at the second position; the exchange column at the first position also receives a second residual liquid, 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 receives an analytical liquid to desorb lithium ions, the exchange column at the third position is moved from the second position.

[0022] The lithium extraction system provided by the present application is provided with a liquid circulation device and an exchange column, and the liquid circulation device is used to transport brine containing lithium ions, analytical solution, and recycled water to the exchange column. Thus, the exchange column is used to adsorb lithium ions, wash, and desorb to complete the process of extracting lithium ions; in this process, the unqualified liquid generated at the third position can also be returned to the second position to be used as the washing liquid of the exchange column, which can not only reduce the water consumption in production, but also inhibit the loss of lithium ions on the exchange column during the elution process through the unqualified liquid and the lithium ions in the recycled water, ensure that the lithium adsorption amount of the exchange column does not change significantly during the elution process, and increase the content of subsequent desorbed lithium ions, thereby increasing the lithium production capacity; and the second residual liquid after washing is also returned to the first position for reuse, which not only further reduces the loss of lithium, but also reduces the amount of brine. It can also dilute the brine, reduce the viscosity and saturation of the brine, reduce the crystallization of the brine in the equipment pipeline and reduce the pressure of the pump, and reduce the flow fluctuation caused by excessive pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. 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.

[0024] Figure 1 It is a schematic structural diagram of a lithium extraction system of an embodiment. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0026] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there can be a central component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time.

[0027] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this application and in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this application includes any and all combinations of one or more of the related listed items.

[0028] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0029] 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 arranged at the first position is used to receive brine and adsorb lithium ions in the brine; the exchange column arranged at the second position is used to receive a first residual liquid, and the first residual liquid includes unqualified liquid produced by the exchange column at the third position; the exchange column at the second position is moved from the first position, and the first residual liquid is used to clean the exchange column at the second position; the exchange column arranged 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 arranged 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.

[0030] Specifically, the liquid circulation device may be an automated device, and the exchange column is disposed on the liquid circulation device and can move on the liquid circulation device, specifically, between a first position, a second position, and a third position of the liquid circulation device.

[0031] Further, the brine is a liquid mixed with lithium ions, and the brine is passed from the brine storage tank into the lithium extraction system, so that the system can extract lithium ions from the brine. Optionally, the exchange column at the first position can be used to receive brine, or to receive a mixture of brine and eluent.

[0032] Optionally, at the first position, the liquid circulation device may have a liquid outlet and a liquid inlet. When the exchange column moves to the first position, the exchange column is located exactly between the liquid outlet and the liquid inlet, and the brine flows out of the liquid outlet and flows through the exchange column arranged at the first position, and then flows back to the liquid circulation device from the liquid inlet. In this process, the exchange column receives the brine and adsorbs the lithium ions in the brine.

[0033] Optionally, at the second position, the liquid circulation device may also have a liquid outlet and a liquid inlet. When the exchange column moves to the second position, the exchange column is exactly located between the liquid outlet and the liquid inlet, and the first residual liquid flows out of the liquid outlet, flows through the exchange column arranged at the second position, and then flows back to the liquid circulation device from the liquid inlet. In this process, the first residual liquid cleans the exchange column at the second position.

[0034] Optionally, at the third position, the liquid circulation device may also have a liquid outlet and a liquid inlet. When the exchange column moves to the third position, the exchange column is located exactly between the liquid outlet and the liquid inlet, and the analytical liquid flows out of the liquid outlet, flows through the exchange column arranged at the third position, and then flows back to the liquid circulation device from the liquid inlet. In this process, the analytical liquid desorbs the lithium ions on the exchange column at the third position.

[0035] The lithium extraction system provided by the present application is provided with a liquid circulation device and an exchange column, and the liquid circulation device is used to transport brine containing lithium ions to the exchange column, so that the exchange column is used to adsorb and desorb lithium ions to complete the process of extracting lithium ions; in this process, the unqualified liquid at the third position can also be returned to the second position to be used as a cleaning liquid for the exchange column, which can not only reduce the water consumption in production, but also inhibit the loss of lithium ions on the exchange column during the elution process through the lithium ions in the first residual liquid, ensure that the lithium adsorption amount of the exchange column does not change significantly during the elution process, and increase the content of subsequent desorbed lithium ions, thereby increasing the lithium production capacity; and the second residual liquid after cleaning is also returned to the first position for reuse, which not only further reduces the loss of lithium and reduces the amount of brine. It can also dilute the brine, reduce the viscosity and saturation of the brine, reduce the crystallization of the brine in the equipment pipeline and reduce the pressure of the pump, and reduce the flow fluctuation caused by excessive pressure.

[0036] In one embodiment, the liquid circulation device also has a fourth position, and the exchange column circulates between the first position, the second position, the third position and the fourth position in sequence; the exchange column arranged 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.

[0037] Optionally, at the fourth position, the liquid circulation device may also have a liquid outlet and a liquid inlet. When the exchange column moves to the fourth position, the exchange column is exactly located between the liquid outlet and the liquid inlet, and the first residual liquid flows out of the liquid outlet, flows through the exchange column arranged at the fourth position, and then flows back to the liquid circulation device from the liquid inlet.

[0038] It is understandable that, since the exchange column at the fourth position is moved from the third position, there is no lithium ion (or there is a very small amount of residual lithium ion) in the exchange column at the fourth position. Therefore, after the first residual liquid flows into and flows out of the exchange column at the fourth position, the composition of the liquid changes very little.

[0039] In one embodiment, 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 has a first position, the leaching zone has a second position, the desorption zone has a third position, and the recovery zone has a fourth position.

[0040] In one embodiment, 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 second position, the third position and the fourth position in sequence.

[0041] Optionally, the sum of the first position, the second position, the third position and the fourth position is 20 to 50, and the number of exchange columns is also 20 to 50. For example, the sum of the first position, the second position, the third position and the fourth position is 20, 25, 30, 35, 40, 45, 50. It can be understood that the number of exchange columns can be the same as or different from the sum of the first position, the second position, the third position and the fourth position.

[0042] For example, Figure 1 As shown, there are thirty positions for setting exchange columns on the liquid circulation device. The number of the first positions is fifteen (respectively A1 to O1), the number of the second positions is four (respectively A2 to D2), the number of the third positions is ten (respectively A3 to J3), and the number of the fourth position is one (A4). In the initial stage, exchange columns 1 to 15 are respectively set on A1 to O1, exchange columns 30 to 27 are respectively set on A2 to D2, exchange columns 26 to 17 are respectively set on A3 to J3, and exchange column 16 is set on A4.

[0043] Further, the exchange columns begin to move, that is, the exchange column 15 on A1 moves to B1, and the exchange column 15 on B1 moves to C1; and so on, until the exchange column 2 on N1 moves to O1. Then, the exchange column 1 on O1 moves to A2; the exchange column 27 on D2 moves to A3; the exchange column 17 on J3 moves to A4; and the exchange column on A4 moves to A1. In this way, the cyclic movement of the exchange columns is completed.

[0044] The lithium extraction system provided in the present application adopts a thirty-column continuous exchange process, by setting four process steps of adsorption zone, elution zone, desorption zone and recovery zone (brine top water zone), and setting thirty exchange columns to circulate, so that each exchange column can pass through the adsorption zone, elution zone, desorption zone and recovery zone (brine top water zone), and then re-enter the adsorption zone to complete a cycle, so as to continuously produce qualified lithium liquid with a magnesium-to-lithium ratio of less than 3 and a lithium content higher than 500ppm.

[0045] In one embodiment, the number of exchange columns is multiple, and the movement interval between two adjacent exchange columns is 8 minutes to 30 minutes. It is understandable that the movement of multiple exchange columns should be at the same speed to ensure that there is no interference between adjacent exchange columns. Optionally, the movement time of the exchange column can be set according to the lithium content of the brine.

[0046] Preferably, there are multiple exchange columns, and the moving interval time between two adjacent exchange columns is 10 minutes to 20 minutes.

[0047] In one embodiment, the multiple first positions include a first sub-position, a second sub-position and a third sub-position; the exchange column arranged at the first sub-position is used to receive primary brine and adsorb lithium ions in the primary brine; the exchange column arranged at the second sub-position is used to receive secondary brine and adsorb lithium ions in the secondary brine; the secondary brine is the residual liquid after the exchange column at the first sub-position adsorbs lithium ions; the exchange column arranged at the third sub-position is used to receive tertiary brine and adsorb lithium ions in the tertiary brine; the tertiary brine is the residual liquid after the exchange column at the second sub-position adsorbs lithium ions.

[0048] Optionally, there are multiple first sub-positions, second sub-positions and third sub-positions, and the number is the same; any first sub-position has a corresponding connected second sub-position and a third sub-position.

[0049] It can be understood that, based on the above-mentioned embodiment, the exchange column in the adsorption zone can receive brine in a "five-in-parallel and three-in-series" manner. It can be understood that the "five-in-parallel and three-in-series" manner is that the number of the first sub-positions, the second sub-positions, and the third sub-positions are all five. The five first sub-positions are in a parallel structure, that is, the liquid outlets of the five first sub-positions discharge and inlet liquid at the same time, and do not interfere with each other; the five first sub-positions are in a parallel structure, that is, the liquid outlets of the five second sub-positions discharge and inlet liquid at the same time, and do not interfere with each other; the five third sub-positions are in a parallel structure, that is, the liquid outlets of the five first sub-positions discharge and inlet liquid at the same time, and do not interfere with each other.

[0050] Optional, such as Figure 1 As shown, 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 the corresponding exchange columns 1 to 5 respectively, so the exchange columns 1 to 5 respectively receive the corresponding primary brine and adsorb the lithium ions in the primary brine.

[0051] Optional, such as Figure 1 As shown, five streams of adsorbed secondary brine will flow out from exchange columns 1 to 5 respectively, and the five streams of secondary brine will flow into corresponding exchange columns 6 to 10 respectively, so exchange columns 6 to 10 respectively receive a corresponding stream of secondary brine and adsorb lithium ions in the secondary brine.

[0052] Optional, such as Figure 1 As shown, five streams of tertiary brine after adsorption will flow out from exchange columns 6 to 10 respectively, and the five streams of tertiary brine will flow into corresponding exchange columns 11 to 15 respectively, so exchange columns 11 to 15 respectively receive a corresponding stream of tertiary brine and adsorb lithium ions in the tertiary brine.

[0053] Therefore, the “five parallels and three series” mentioned above include the flow paths of five brine streams, namely: O1→J1→E1, N1→I1→D1, M1→H1→C1, L1→G1→B1 and K1→F1→A1.

[0054] In other embodiments, the “five in parallel and three in series” respectively include five brine flow paths, which can also be: O1→F1→A1, N1→G1→B1, M1→H1→C1, L1→I1→D1 and K1→J1→E1.

[0055] Further, on the basis of the above embodiment, the exchange column will also move in the first position by rotation. Each exchange column absorbs a corresponding brine as it rotates one position. For example, when the exchange column 15 on A1 moves to B1, it switches from receiving a tertiary brine to receiving another tertiary brine. Of course, when the exchange column 11 on E1 moves to F1, it switches from receiving a tertiary brine to receiving a secondary brine. Similarly, when the exchange column 6 on J1 moves to K1, it switches from receiving a secondary brine to receiving a primary brine.

[0056] Therefore, starting from the first adsorption of tertiary brine when entering the exchange column of A1, until it rotates to O1, each exchange column has to adsorb secondary brine fifteen times (tertiary brine, secondary brine and primary brine three times each).

[0057] In other embodiments, the method of "seven in parallel and two in series" or "eight in parallel and two in series" may also be adopted. Among them, "seven in parallel" and "eight in parallel" may refer to the "five in parallel" mentioned above, and "two in series" may refer to the "three in series" mentioned above, and no further explanation will be given 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 may be increased. Therefore, while ensuring that the total amount of the thirty columns remains unchanged, the number of different given positions can be adaptively adjusted.

[0058] 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, it can be understood that the exchange column located on A1 (exchange column 15) has the strongest adsorption capacity, because its front end is a desorption process and has not been adsorbed by brine. 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 directly discharged to the salt field, and a small part is used as the inlet water of the fourth position of the recovery area.

[0059] In one embodiment, the lithium extraction system includes a working surface, and the exchange column includes a lower end close to the working surface and an upper end away from the working surface; for the exchange column arranged at the first sub-position, primary brine is introduced from the upper end, and residual liquid after adsorption flows out from the lower end; for the exchange column arranged at the second sub-position, secondary brine is introduced from the upper end, and residual liquid after adsorption of lithium ions flows out from the lower end; for the exchange column arranged at the third sub-position, tertiary brine is introduced from the upper end, and residual liquid after adsorption of lithium ions flows out from the lower end.

[0060] Specifically, the working surface can be the surface of the ground or a workbench. The structure of the exchange column can be cylindrical, 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 like this.

[0061] Optionally, based on the above implementation, the liquid inlet method of the exchange column may not be completely the same. Figure 1 As shown, the liquid outlet and liquid inlet at the first sub-position are respectively located at the upper end and the lower end of the exchange column, so the exchange column at the first sub-position receives brine from the liquid outlet at the upper end, and discharges brine to the liquid inlet at the lower end. The liquid outlet and liquid inlet at the second sub-position are respectively located at the lower end and the upper end of the exchange column, so the exchange column at the second sub-position receives brine from the liquid outlet at the lower end, and discharges brine to the liquid inlet at the upper end. The exchange column at the third sub-position can refer to the first sub-position, and will not be described in detail here.

[0062] Optionally, all the exchange columns at the first position may 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.

[0063] Optionally, the first sub-position and the third sub-position may absorb lithium ions in a bottom-in-top-out manner, while the second sub-position may absorb lithium ions in a top-in-bottom-out manner.

[0064] Optionally, the first sub-position and the second sub-position may absorb lithium ions in a top-in, bottom-out manner, while the third sub-position may absorb lithium ions in a bottom-in, top-out manner.

[0065] By adopting the process of top-in and bottom-out or a mixture of top-in and bottom-out and bottom-in and top-out, each exchange column has the opportunity of top-in and bottom-out and bottom-in and top-out; thereby, the lithium content adsorbed in the exchange column is basically consistent in the upper and lower positions, 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 column due to clogging, thereby reducing the probability of breakage and clogging of the adsorbent in the exchange column.

[0066] In one embodiment, the flow rate of the brine at the first position is 3BV / h to 10BV / h. Preferably, the flow rate of the brine at the first position is 3BV / h to 7BV / h.

[0067] Optionally, the lithium content in the brine is 100 mg / L to 1500 mg / L. Preferably, the lithium content in the brine is greater than 150 mg / L.

[0068] Optionally, the lithium adsorption amount of the exchange column after passing through O1 ranges from 1 mg / g to 5 mg / g. Preferably, the lithium adsorption amount of the exchange column after passing through O1 ranges from 2 mg / g to 4 mg / g.

[0069] In one embodiment, there are multiple second positions, and the first residual liquid is introduced into the exchange column arranged at the second position from the upper end, and the residual liquid after washing flows out from the lower end.

[0070] Specifically, the exchange column at the second position can adopt a liquid inlet method of top-in and bottom-out. Figure 1 As shown, the number of the second positions may be four. The initial liquid inlet position of the first residual liquid is on D2.

[0071] Therefore, the flow pattern of the first residual liquid at multiple second positions is: entering the upper end of the exchange column from the liquid outlet of D2, and flowing out from the lower end of the exchange column to the liquid outlet of D2; then entering the upper end of the exchange column through the liquid outlet of C2, and flowing out from the lower end of the exchange column to the liquid outlet of C2, and in turn until A1 to complete the elution process of the elution zone.

[0072] When the exchange column on O1 moves to A2 (such as Figure 1 As shown, the exchange column 1 moves to A2), and the exchange column on A2 actually washes the residual liquid washed at the previous position (B2). In addition, the second residual liquid after washing 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 second residual liquid is mixed with the primary brine).

[0073] Since the lithium content in the first residual liquid is high, the benefit of setting the second position is not only to reduce the loss of lithium and the amount of brine, but also to dilute the brine, reduce the viscosity and saturation of the brine, reduce the crystallization of the brine in the equipment pipeline and reduce the pressure of the pump, and reduce the flow fluctuation caused by excessive pressure. After the four fourth positions are washed, the exchange column can be gradually washed clean, so that most of the impurity ions are washed away.

[0074] In one embodiment, the flow rate of the first residual liquid at the second position is 2 BV / h to 10 BV / h. Preferably, the flow rate of the first residual liquid at the second position is 4 BV / h to 8 BV / h.

[0075] Optionally, the lithium content in the first residual liquid is 100 ppm to 600 ppm. Preferably, the lithium content in the first residual liquid is 200 ppm to 500 ppm.

[0076] Optionally, the ratio of magnesium to lithium in the first residual liquid is less than 3:1, and the magnesium content ranges from 50 mg / L to 1000 mg / L. Preferably, the ratio of magnesium to lithium is less than 2:1, and the magnesium content ranges from 50 mg / L to 500 mg / L.

[0077] Optionally, the total amount of liquid introduced into the second position is 3BV to 6BV. Preferably, the total amount of liquid introduced into the second position is 4BV to 5BV.

[0078] In one embodiment, the exchange column arranged at the second position is also used to receive the third residual liquid, and the third residual liquid includes part of the residual liquid after the exchange column at the third position desorbs lithium ions. It can be understood that the second position receives the unqualified liquid (third residual liquid) after desorption and the first residual liquid. The use of these two streams of recycled water instead of pure water or tap water for water washing can greatly reduce the amount of water used in production, and the lithium ions contained in the recycled water can inhibit the loss of lithium ions on the adsorbent during the elution process, ensuring that the lithium adsorption amount 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 increasing the lithium production capacity.

[0079] In one embodiment, there are multiple third positions, and the exchange column arranged at the third position has the analytical liquid 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 qualified liquid.

[0080] Specifically, the exchange column at the third position can adopt a liquid inlet method of top-in and bottom-out. Figure 1 As shown, the number of the third positions may be ten. The initial inlet position of the analytical solution is at J3.

[0081] Therefore, the flow pattern of the analytical liquid at multiple third positions is: entering the upper end of the exchange column from the liquid outlet of J3, and flowing out from the lower end of the exchange column to the liquid outlet of J3; then entering the upper end of the exchange column through the liquid outlet of I3, and flowing out from the lower end of the exchange column to the liquid outlet of I3, and then to A3 to complete the desorption process of the desorption zone.

[0082] When the exchange column on D2 moves to A3 (such as Figure 1 As shown, the exchange column 27 moves to A3), and the exchange column on A3 actually uses the water desorbed from the previous position (B3). In addition, the unqualified liquid (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 elution water in the upper position remaining in the exchange column and some desorption water with low lithium concentration, collectively referred to as unqualified liquid (third residual liquid). After the unqualified liquid flows out, the next to come out is the qualified liquid, which is the target product of the continuous ion exchange system.

[0083] Optionally, the volume range of the unqualified liquid is 0.5 BV to 1 BV. Preferably, the volume range of the unqualified liquid is 0.6 BV to 0.8 BV.

[0084] In one embodiment, the flow rate of the analytical solution at the third position is 6 BV / h to 20 BV / h. Preferably, the flow rate of the analytical solution at the third position is 10

[0085] Optionally, the analytical solution introduced into J1 is pure water or tap water, with a conductivity of less than 200 us / cm and a temperature range of 30° C. to 60° C. Preferably, the analytical solution has a conductivity of 10 us / cm to 50 us / cm and a temperature range of 35° C. to 45° C.

[0086] In one embodiment, the fourth position is one, and the first residual liquid enters from the lower end of the exchange column set at the fourth position and flows out from the upper end. The outflowing first residual liquid and the third residual liquid are jointly merged into the exchange column set at the second position.

[0087] Specifically, the exchange column at the fourth position can adopt a bottom-in-top-out liquid inlet method. Figure 1 As shown, the exchange column 17 moves to A4), and then enters the recovery zone (brine top water zone).

[0088] If the top-in and bottom-out method is adopted, the incoming brine is easy to form a coagulation layer with the water in the column, and the impurity ion content of the recovered water is high. The qualified recyclable water is less than 0.5BV. If the bottom-in and top-out method is adopted, 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 the unqualified water as the inlet water for elution.

[0089] After the column goes through the above four processes, it re-enters the adsorption stage to start a new cycle. This process can produce qualified liquid continuously for 24 hours to ensure the production capacity of lithium extraction.

[0090] In one embodiment, the flow rate of the first residual liquid at the fourth position is 1 BV / h to 6 BV / h. Preferably, the flow rate of the first residual liquid at the fourth position is 2 BV / h to 4 BV / h.

[0091] Optionally, the amount of water introduced into the fourth position by the first residual liquid is 0.3BV to 1BV. Preferably, the amount of water introduced into the fourth position by the first residual liquid is 0.5BV to 0.7BV.

[0092] In one embodiment, the present application also provides a lithium extraction method, comprising the following steps:

[0093] The exchange column at the first position receives brine and adsorbs lithium ions in the brine.

[0094] The exchange column at the second position receives the first residual liquid, which includes the unqualified liquid produced by the exchange column at the third position; the exchange column at the second position is moved from the first position, and the first residual liquid is used to clean the exchange column at the second position.

[0095] The exchange column at the first position also receives a second residual liquid, which includes a washing liquid flowing out after the exchange column at the second position is cleaned.

[0096] The exchange column at the third position receives the analytical solution to desorb lithium ions, and the exchange column at the third position moves from the second position.

[0097] The lithium extraction method provided in the present 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.

[0098] Second, the desorption flow rate can be adjusted in different ranges according to the lithium content of the adsorbed brine, and the average lithium desorption rate reaches about 100%, ensuring that the adsorbed lithium can be completely desorbed. It will not cause the problem of reduced lithium yield, gradual reduction of yield due to incomplete desorption, and gradual increase of lithium content in the adsorption tail liquid.

[0099] Third, the lithium extraction method uses more exchange columns, and the number of exchange columns in the elution zone and the number of exchange columns in the desorption zone are reasonably distributed and utilized, which can improve the production capacity, so that the lithium extraction method can produce qualified liquid for 24 hours continuously. The lithium content of the qualified liquid is higher than 500ppm, and can reach up to about 1400mg / L.

[0100] Fourth, this lithium extraction method fully considers the reuse of water. The desorbed solution has a high lithium content, which saves more than 20% water compared with the traditional single-tower process and the eighteen-column continuous desorption process, and the maximum water saving can reach about 50%.

[0101] Fifth, the lithium extraction method can use brine saturated with a high magnesium-to-lithium ratio, with a magnesium-to-lithium ratio greater than 500. The qualified liquid obtained by the lithium extraction method has a low magnesium-to-lithium ratio, generally less than 2:1. This has a great effect on reducing the steps and energy consumption for the subsequent membrane segment method to refine the qualified liquid.

[0102] The technical solution of the present invention will be further described below in conjunction with embodiments and drawings.

[0103] Example 1

[0104] Brine 1 is used, and the composition of brine 1 is shown in Table 1. The specific steps of lithium extraction are as follows:

[0105] 1) Brine filtration: use one or two of bag filter, backwash filter and candle filter. The filtration accuracy is less than 25 μm, and the preferred filtration accuracy range is 3 μm to 6 μm.

[0106] 2) Brine adsorption: Adsorption is carried out using exchange columns and liquid circulation devices. Among them, the number of the first positions in the adsorption zone is 15, and a five-in-three-in-one process is adopted, and a mixed process of top-in and bottom-out and bottom-in and top-out is adopted. The brine flow rate is 8.6BV / h, and the exchange column rotates once every 12 minutes and moves 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. Among them, the second sub-position is bottom-in and top-out, and the remaining positions are top-in and bottom-out. The feed is a mixture of eluent and brine.

[0107] 3) Elution: The number of second positions in the elution zone is 4, and a series process of top-in and bottom-out is adopted. The flow rate of the elution section is 6BV / h, and the total water washing volume is 4.8BV. The exchange column rotates once every 12 minutes and moves one position. The unqualified liquid (third residual liquid) after desorption and the reflux liquid (first residual liquid) after adsorption are introduced.

[0108] 4) Lithium desorption: The desorption zone adopts countercurrent desorption, and each exchange column enters with water desorbed from the previous position. The volume of unqualified liquid is 0.69BV, and the unqualified liquid is recovered as elution water and enters the low calcium and magnesium water tank as elution 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 refining and removal of impurity ions, battery-grade lithium carbonate is produced. The flow rate of the desorption section is 15.24BV / h. The desorption section position 17 enters with pure water, the conductivity is 20us / cm, and the water temperature is 40°C.

[0109] 5) Recovery: The exchange column enters the fourth position from the third position, and then enters the recovery area. There is only one fourth position. The bottom-in and top-out method is adopted. The flow rate range of the first residual liquid (brine top water) is 2.6BV / h. The range of the first residual liquid volume is 0.52BV.

[0110] Table 1

[0111]

[0112] Example 2

[0113] Brine 2 was used, and the composition of brine 2 is shown in Table 2. Among them, the brine flow rate in the adsorption zone and the elution water flow rate in the desorption zone were changed, and the rest were the same. The specific steps of lithium extraction are as follows:

[0114] The brine flow rate in the adsorption section and the pure water flow rate in the desorption section have changed, and the rest are the same. The specific steps are as follows

[0115] 1) Brine filtration: use one or two of bag filter, backwash filter and candle filter. The filtration accuracy is less than 25 μm, and the preferred filtration accuracy range is 3 μm to 6 μm.

[0116] 2) Brine adsorption: Adsorption is carried out using exchange columns and liquid circulation devices. Among them, the number of the first positions in the adsorption zone is 15, and a five-in-three-in-one process is adopted, and a mixed process of top-in and bottom-out and bottom-in and top-out is adopted. The brine flow rate is 5.8BV / h, and the exchange column rotates once every 12 minutes and moves 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. Among them, the second sub-position is bottom-in and top-out, and the remaining positions are top-in and bottom-out. The feed is a mixture of eluent and brine.

[0117] 3) Elution: The number of second positions in the elution zone is 4, and a series process of top-in and bottom-out is adopted. The flow rate of the elution section is 6BV / h, and the total water washing volume is 4.8BV. The exchange column rotates once every 12 minutes and moves one position. The unqualified liquid (third residual liquid) after desorption and the reflux liquid (first residual liquid) after adsorption are introduced.

[0118] 4) Lithium desorption: The desorption zone adopts countercurrent desorption, and each exchange column enters with water desorbed from the previous position. The volume of unqualified liquid is 0.69BV, and the unqualified liquid is recovered as elution water and enters the low calcium and magnesium water tank as elution 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 refining and removal of impurity ions, battery-grade lithium carbonate is produced. The flow rate of the desorption section is 16.31BV / h. The desorption section position 17 enters with pure water, the conductivity is 20us / cm, and the water temperature is 40°C.

[0119] 5) Recovery: The exchange column enters the fourth position from the third position, and then enters the recovery area. There is only one fourth position. The bottom-in and top-out method is adopted. The flow rate range of the first residual liquid (brine top water) is 2.6BV / h. The range of the first residual liquid volume is 0.52BV.

[0120] Table 2

[0121]

[0122] Example 3

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

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

[0125] 2) Brine adsorption: Adsorption is carried out using exchange columns and liquid circulation devices. Among them, the number of the first positions in the adsorption zone is 15, and a five-in-three-in-one process is adopted, and a mixed process of top-in and bottom-out and bottom-in and top-out is adopted. The brine flow rate is 2.47BV / h, and the exchange column rotates once every 12 minutes and moves 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. Among them, the second sub-position is bottom-in and top-out, and the remaining positions are top-in and bottom-out. The feed is a mixture of eluent and brine.

[0126] 3) Elution: The number of second positions in the elution zone is 4, and a series process of top-in and bottom-out is adopted. The flow rate of the elution section is 6BV / h, and the total water washing volume is 4.8BV. The exchange column rotates once every 12 minutes and moves one position. The unqualified liquid (third residual liquid) after desorption and the reflux liquid (first residual liquid) after adsorption are introduced.

[0127] 4) Lithium desorption: The desorption zone adopts countercurrent desorption, and each exchange column enters with water desorbed from the previous position. The volume of unqualified liquid is 0.69BV, and the unqualified liquid is recovered as elution water and enters the low calcium and magnesium water tank as elution 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 refining and removal of impurity ions, battery-grade lithium carbonate is produced. The flow rate of the desorption section is 14.16BV / h. The desorption section No. 17 position enters with pure water, the conductivity is 20us / cm, and the water temperature is 50℃.

[0128] 5) Recovery: The exchange column enters the fourth position from the third position, and then enters the recovery area. There is only one fourth position. The bottom-in and top-out method is adopted. The flow rate range of the first residual liquid (brine top water) is 2.6BV / h. The range of the first residual liquid volume is 0.52BV.

[0129] Table 3

[0130]

[0131] The above examples 1-3 are all about starting the equipment for the first time, and the lithium extraction process is 6 hours, that is, after the exchange column has completely circulated a process, sampling and analysis are performed. Examples 1-3 all use qualified liquid that has circulated for 24 hours, and use ICP equipment to analyze the ion content.

[0132] The adsorption extraction rate is = (1- lithium ion content of adsorption tail liquid / lithium content of brine) * 100%

[0133] Desorption rate = (qualified liquid lithium content * qualified liquid volume) / (brine lithium content * total volume of brine * adsorption extraction rate) * 100%

[0134] The analysis results are shown in Table 4 below:

[0135] Table 4

[0136]

[0137] From the above test results, it can be seen that the qualified liquid produced by this process at room temperature has a high extraction rate. If the lithium concentration of the brine increases, the extraction rate will be above 90%. The desorption rate in the desorption zone is about 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 more than 500 to less than 2. Lay a solid foundation for the precipitation of qualified battery-grade lithium carbonate. This process requires about 300-500 tons of pure water per ton of lithium carbonate, which is more than 20% less water than the external conventional continuous desorption process of about 600.

[0138] 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, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0139] What is disclosed above is only a preferred embodiment of the present application, and it 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 implementing the above embodiment and equivalent changes made according to 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 disposed at the first position is used to receive brine and adsorb lithium ions in the brine; The exchange column disposed at the second position is used to receive a first residual liquid, wherein the first residual liquid includes an unqualified liquid produced by the exchange column at the third position; The exchange column at the second position is moved from the first position, and the first residual liquid is used to clean the exchange column at the second position; The exchange column disposed at the first position is also used to receive 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; The exchange column disposed 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; The liquid circulation device also has a fourth position, and the exchange column cyclically moves among the first position, the second position, the third position and the fourth position in sequence; The exchange column arranged 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. The exchange column at the fourth position is moved from the third position, and the exchange column arranged at the second position is also used to receive the third residual liquid, and the third residual liquid includes the recovered water discharged from the fourth position.

2. The lithium extraction system according to claim 1, characterized in that: 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 multiple first positions in sequence, and then passes through the second position, the third position, and the fourth position in sequence.

3. The lithium extraction system according to claim 2, characterized in that: The total number of the first position, the second position, the third position and the fourth position is 20 to 50.

4. The lithium extraction system according to claim 2, characterized in that: The plurality of said first positions include a first sub-position, a second sub-position and a third sub-position; The exchange column arranged at the first sub-position is used to receive the primary brine and adsorb the lithium ions in the primary brine; The exchange column arranged at the second sub-position is used to receive secondary brine and adsorb lithium ions in the secondary brine; the secondary brine is the residual liquid after the exchange column at the first sub-position adsorbs lithium ions; The exchange column arranged at the third sub-position is used to receive tertiary brine and adsorb lithium ions in the tertiary brine; the tertiary brine is the residual liquid after the exchange column at the second sub-position adsorbs lithium ions.

5. The lithium extraction system according to claim 4, characterized in that: The first sub-position, the second sub-position and the third sub-position are multiple and the number is the same; any first sub-position has a corresponding connected second sub-position and a third sub-position.

6. The lithium extraction system according to claim 5, characterized in that: The lithium extraction system comprises a working surface, and the exchange column comprises a lower end close to the working surface and an upper end away from the working surface; The exchange column is arranged at the first sub-position, the primary brine is introduced from the upper end, and the residual liquid after adsorption flows out from the lower end; The exchange column is arranged at the second sub-position, the secondary brine is introduced from the upper end, and the residual liquid after adsorbing lithium ions flows out from the lower end; The exchange column is arranged at the third sub-position, the tertiary brine is introduced from the upper end, and the residual liquid after adsorbing lithium ions flows out from the lower end.

7. The lithium extraction system according to claim 6, characterized in that: There are multiple second positions, and the exchange columns are arranged at the second positions. The first residual liquid is introduced from the upper end, and the residual liquid after washing flows out from the lower end.

8. The lithium extraction system according to claim 7, characterized in that: There are multiple third positions, and the exchange columns are arranged at the third positions. The analytical liquid 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 qualified liquid.

9. The lithium extraction system according to claim 1, characterized in that: There are multiple exchange columns, and the moving interval time between two adjacent exchange columns is 8 minutes to 30 minutes.

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

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

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

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

14. A method for extracting lithium, characterized in that: include: The exchange column at the first position receives brine and adsorbs lithium ions in the brine; The exchange column at the second position receives the first residual liquid and the third residual liquid, wherein the first residual liquid includes the unqualified liquid produced by the exchange column at the third position; The exchange column at the second position is moved from the first position, the first residual liquid is used to clean the exchange column at the second position, and the third residual liquid includes the recycled water discharged from the fourth position; The exchange column at the first position also 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; The exchange column at the third position receives the analytical solution to desorb lithium ions, and the exchange column at the third position is moved from the second position; The exchange column at the fourth position receives the residual liquid after the exchange column at the first position adsorbs lithium ions, and the residual liquid pushes 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.

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