Ocean platform production water lithium extraction system and method based on cyclone separation

Abstract

The invention discloses a system and a method for extracting lithium from ocean platform production water based on cyclone separation, and belongs to the technical field of ocean resource recovery. The system mainly comprises a mixed extraction tank, an acid liquor regeneration tank and a PLC (Programmable Logic Controller) control system. The core innovation of the vertical mixed extraction tank is that the mixed extraction area, the first-stage cyclone separation module and the second-stage cyclone separation module are used as internal components and are integrated in the vertical mixed extraction tank from top to bottom, so that the extreme compactness of extraction and multi-stage separation is realized. Production water and an extraction agent are mixed at the bottom of the tank, oil and water are rapidly separated through the first-stage rotational flow module, an oil phase is deeply purified through the second-stage rotational flow module, and finally the oil phase is discharged from the top of the tank and enters the acid liquid regeneration tank. In the acid liquid regeneration tank, the lithium-rich oil phase is in countercurrent contact with hydrochloric acid for reverse extraction, and the regenerated oil phase is returned for recycling; and a separation inner component integrated in the tank realizes rapid phase separation after reverse extraction. The PLC system monitors the pH value in the regeneration tank in real time, and when the pH value reaches 5.5-6.0, lithium-rich liquid is automatically discharged, and hydrochloric acid is supplemented.

Description

Technical Field

[0001] This invention belongs to the field of lithium resource recovery technology, and particularly relates to a system and method for producing water-extracted lithium from an offshore platform based on cyclone separation. Background Technology

[0002] Solvent extraction has been applied in lithium extraction from salt lakes, but it faces significant challenges when processing production water from offshore platforms, which has low lithium concentrations, high magnesium-to-lithium ratios, and may contain oil. Traditional extraction and separation equipment, such as mixing-clarification tanks, suffers from problems such as large footprint, long residence times, easy formation of stable emulsions, and low separation efficiency. On space-constrained offshore platforms, these drawbacks are further amplified.

[0003] Hydrocyclones, as highly efficient centrifugal separation devices, offer advantages such as simple structure, rapid separation, and minimal footprint. However, a single hydrocyclone has limited processing capacity and is sensitive to feed fluctuations, making it difficult to guarantee stable separation results when directly used for processing large volumes of production water or easily emulsified extraction systems. Simply connecting multiple individual hydrocyclones in parallel leads to complex piping and uneven liquid distribution. Therefore, there is an urgent need for an innovative solution that efficiently integrates hydrocyclone separation technology into solvent extraction processes, achieving a compact and continuous operation of the entire process.

[0004] The closest prior art is CN109097791B (“Method and Apparatus for Lithium Extraction from Seawater Based on Lithium-ion Solid Electrolyte”). This patent discloses a method for extracting lithium ions from seawater by using a lithium-ion solid electrolyte membrane to separate the cathode and anode regions and depositing metallic lithium in the seawater in the anode region.

[0005] The existing technical problems include:

[0006] 1. Although this method can extract lithium directly from seawater, it relies on electrolytic deposition of metallic lithium, which consumes a lot of electrical energy, has a complex process, and is inefficient and costly when applied to low-concentration lithium resources (such as seawater with extremely low lithium content).

[0007] 2. In addition, this technology mainly focuses on the selection of membranes and solutions in electrochemical lithium extraction devices and the deposition of metallic lithium. However, there are few systematic solutions for the treatment of suspended solids, oil, and impurities (such as various dissolved ions, oil-water separation, etc.) in seawater, which makes it difficult to promote its application in the actual production water environment of marine platforms. Summary of the Invention

[0008] To address the problems existing in the prior art, this invention provides a system and method for producing water-based lithium on a marine platform based on multi-core tube cyclone separation.

[0009] This invention is implemented as follows: a water-based lithium extraction system for offshore platforms based on cyclone separation includes:

[0010] Mixing extraction tank, acid regeneration tank, and PLC control system;

[0011] The mixing extraction tank is a vertical tank, which integrates a mixing extraction zone, a primary cyclone separation module, and a secondary cyclone separation module as internal components from bottom to top.

[0012] The mixing extraction tank is equipped with a production water inlet and an extractant inlet at the bottom, an oil phase outlet at the top, and an aqueous phase outlet at the side or bottom.

[0013] The mixing and extraction zone is located at the bottom of the tank and is used to ensure that the production water and the extractant are fully mixed.

[0014] The primary hydrocyclone separation module is located above the mixing and extraction zone and includes a liquid distributor and 3-12 hydrocyclones connected in parallel. The inlet of the liquid distributor is connected to the mixing and extraction zone, and its outlet is connected to the inlet of each hydrocyclone in a one-to-one correspondence.

[0015] The secondary cyclone separation module is located above the primary cyclone separation module. Its inlet is connected to the oil phase outlet of the primary cyclone separation module, its oil phase outlet is connected to the oil phase outlet of the mixing extraction tank, and its aqueous phase outlet is connected to the inner cavity of the tank.

[0016] The oil phase outlet of the mixing extraction tank is connected to the oil phase inlet at the bottom of the acid regeneration tank via a pipeline, and comes into countercurrent contact with the acid to perform ion exchange;

[0017] The acid regeneration tank is equipped with an acid circulation and distribution system, an oil phase distributor, integrated separation internal components, a pH sensor, a lithium-rich liquid discharge port, and an acid replenishment port. The regenerated oil phase outlet at the top is connected back to the extractant inlet of the mixing extraction tank via a pipeline.

[0018] The PLC control system is connected to the control valves on the pH sensor, the lithium-rich liquid discharge port, and the acid replenishment port.

[0019] Furthermore, the liquid distributor of the primary cyclone separation module is a porous tube or annular tube structure, and the sum of its total outlet orifice areas is less than the cross-sectional area of ​​the inlet pipe to ensure uniform pressure distribution.

[0020] Furthermore, the secondary cyclone separation module is a coalescing hydrocyclone assembly, in which the inner wall of the cone section or the surface of the central rod of each hydrocyclone is coated with an oleophilic and hydrophobic material layer.

[0021] Furthermore, the integrated separation internal components in the acid regeneration tank are a cyclone plate group or a small hydrocyclone group, which are set above the countercurrent contact area to quickly separate the oil-water mixture formed after back-extraction.

[0022] Furthermore, the mixing and extraction zone is equipped with a static mixing unit or a dynamic stirrer.

[0023] Furthermore, the PLC control system is configured to automatically open the discharge valve to discharge lithium-rich liquid and replenish hydrochloric acid with a concentration of 1-3 mol / L when the pH value in the acid regeneration tank is detected to rise to 5.5-6.0.

[0024] Another object of the present invention is to provide a lithium extraction method comprising the following steps:

[0025] S1: Marine platform production water with an oil content reduced to below 5-10 ppm is pumped into the mixing extraction zone at the bottom of the mixing extraction tank along with recycled extractant for deep mixing extraction;

[0026] S2: The extracted oil-water mixture enters the first-stage hydrocyclone separation module upwards, and is evenly distributed to each hydrocyclone by the liquid distributor for primary centrifugal separation; the separated aqueous phase is discharged downwards from the bottom water phase outlet of the tank, and the oil phase enters the second-stage hydrocyclone separation module upwards.

[0027] S3: The oil phase undergoes deep separation in the two-stage cyclone separation module to further remove the entrained water phase, and the purified lithium-rich oil phase is discharged from the oil phase outlet at the top of the tank.

[0028] S4: The lithium-rich oil phase enters from the bottom of the acid regeneration tank, is dispersed by the distributor and flows upward, and comes into countercurrent contact with the 1-3 mol / L hydrochloric acid solution in the tank to carry out the back-extraction reaction;

[0029] S5: After back-extraction, the mixture is rapidly separated in the integrated separation internal components inside the tank. The regenerated oil phase is exported from the top of the tank and returned to the mixing extraction tank for recycling, while the lithium acid-containing liquid is retained at the bottom of the tank.

[0030] S6: Monitors the pH value of the acid solution at the bottom of the tank in real time. When the pH value reaches 5.5-6.0, it automatically discharges the lithium-rich back-extraction solution and replenishes fresh hydrochloric acid.

[0031] Furthermore, in step S2, the inlet pressure of the primary cyclone separation module is controlled to be 0.15-0.35 MPa to achieve rapid and effective separation of the oil and water phases.

[0032] Furthermore, in step S4, the volumetric flow rate ratio of the oil phase to the acid is controlled to be 8:1 to 15:1, and the countercurrent contact time is 8-20 minutes.

[0033] Furthermore, in step S6, the discharged lithium-rich back-extraction solution is transported to the subsequent evaporation and crystallization unit to produce lithium chloride or lithium carbonate products.

[0034] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0035] High-efficiency separation: The core separation device is a cyclone separation module, which uses centrifugal force to achieve millisecond-level rapid separation, greatly improving the throughput and efficiency of the extraction system, and effectively overcoming the separation difficulties caused by emulsions.

[0036] Compact structure: Multiple hydrocyclones are integrated into a single shell, forming a highly modular separation core. The piping is simple and the footprint is much smaller than that of traditional clarifiers, perfectly meeting the space constraints of offshore platforms.

[0037] Stable operation and strong resistance to fluctuations: The multi-core tube parallel design makes the system insensitive to flow fluctuations. Even if the operating conditions of a single hydrocyclone change, the overall separation effect can remain stable, ensuring the continuity of the entire lithium extraction process.

[0038] Closed-loop recycling and low cost: By integrating the back-extraction regeneration unit, the online regeneration and recycling of the extractant are realized, which significantly reduces reagent consumption and operating costs and improves the economics of the process.

[0039] High degree of automation: Through the linkage between pH sensor and PLC controller, the acid replenishment and replacement are automated, reducing manual intervention and making it suitable for long-term stable operation on unmanned or minimally staffed platforms. Attached Figure Description

[0040] Figure 1 This is a structural block diagram of a marine platform lithium extraction system based on multi-core tube cyclone separation, provided in an embodiment of the present invention.

[0041] Figure 2 This is a flowchart of a method for producing water-based lithium from a marine platform based on multi-core tube cyclone separation, provided in an embodiment of the present invention.

[0042] Figure 1 In the middle section: 1. Mixing extraction tank; 2. Mixing extraction zone; 3. Liquid distributor; 4. Primary cyclone separation module; 5. Secondary cyclone separation module; 6. Oil phase outlet. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0044] like Figure 1 As shown in the figure, an embodiment of the present invention provides a marine platform water extraction lithium production system based on multi-core tube cyclone separation, comprising:

[0045] Mixing extraction tank 1, acid regeneration tank and PLC control system;

[0046] The mixing extraction tank 1 is a vertical tank, and its interior is integrated from bottom to top with a mixing extraction zone 2, a primary cyclone separation module 4 and a secondary cyclone separation module 5 as internal components;

[0047] The bottom of the mixing extraction tank is provided with a production water inlet and an extractant inlet, the top is provided with an oil phase outlet 6, and the side or bottom is provided with an aqueous phase outlet;

[0048] The mixing and extraction zone is located at the bottom of the tank and is used to ensure that the production water and the extractant are fully mixed.

[0049] The primary hydrocyclone separation module 4 is located above the mixing and extraction zone, and includes a liquid distributor and 3-12 hydrocyclones connected in parallel. The inlet of the liquid distributor is connected to the mixing and extraction zone, and its outlet is connected to the inlet of each hydrocyclone in a one-to-one correspondence.

[0050] The secondary cyclone separation module 5 is located above the primary cyclone separation module. Its inlet is connected to the oil phase outlet of the primary cyclone separation module, its oil phase outlet is connected to the oil phase outlet of the mixing extraction tank, and its aqueous phase outlet is connected to the inner cavity of the tank.

[0051] The oil phase outlet 6 of the mixing extraction tank 1 is connected to the oil phase inlet at the bottom of the acid regeneration tank through a pipeline, and comes into countercurrent contact with the acid to perform ion exchange;

[0052] The acid regeneration tank is equipped with an acid circulation and distribution system, an oil phase distributor, integrated separation internal components, a pH sensor, a lithium-rich liquid discharge port, and an acid replenishment port. The regenerated oil phase outlet at the top is connected back to the extractant inlet of the mixing extraction tank via a pipeline.

[0053] The PLC control system is connected to the control valves on the pH sensor, the lithium-rich liquid discharge port, and the acid replenishment port.

[0054] The liquid distributor of the primary cyclone separation module provided in this embodiment of the invention is a porous tube or annular tube structure, and the sum of the total outlet orifice areas is less than the cross-sectional area of ​​the inlet pipe to ensure uniform pressure distribution.

[0055] The secondary cyclone separation module provided in this embodiment of the invention is a coalescing hydrocyclone group, in which the inner wall of the cone section or the surface of the central rod of a single hydrocyclone is coated with an oleophilic and hydrophobic material layer.

[0056] The integrated separation internal components in the acid regeneration tank provided in this embodiment of the invention are a cyclone plate group or a small hydrocyclone group, which are set above the countercurrent contact zone and are used to quickly separate the oil-water mixture formed after back-extraction.

[0057] The mixing and extraction zone provided in this embodiment of the invention is equipped with a static mixing unit or a dynamic stirrer.

[0058] The PLC control system provided in this embodiment of the invention is configured to automatically open the discharge valve to discharge lithium-rich liquid and replenish hydrochloric acid with a concentration of 1-3 mol / L when the pH value in the acid regeneration tank is detected to rise to 5.5-6.0.

[0059] like Figure 2 As shown in the figure, an embodiment of the present invention provides a lithium extraction method, which includes the following steps:

[0060] S1: Marine platform production water with an oil content reduced to below 5-10 ppm is pumped into the mixing extraction zone at the bottom of the mixing extraction tank along with recycled extractant for deep mixing extraction;

[0061] S2: The extracted oil-water mixture enters the first-stage hydrocyclone separation module upwards, and is evenly distributed to each hydrocyclone by the liquid distributor for primary centrifugal separation; the separated aqueous phase is discharged downwards from the bottom water phase outlet of the tank, and the oil phase enters the second-stage hydrocyclone separation module upwards.

[0062] S3: The oil phase undergoes deep separation in the two-stage cyclone separation module to further remove the entrained water phase, and the purified lithium-rich oil phase is discharged from the oil phase outlet at the top of the tank.

[0063] S4: The lithium-rich oil phase enters from the bottom of the acid regeneration tank, is dispersed by the distributor and flows upward, and comes into countercurrent contact with the 1-3 mol / L hydrochloric acid solution in the tank to carry out the back-extraction reaction;

[0064] S5: After back-extraction, the mixture is rapidly separated in the integrated separation internal components inside the tank. The regenerated oil phase is exported from the top of the tank and returned to the mixing extraction tank for recycling, while the lithium acid-containing liquid is retained at the bottom of the tank.

[0065] S6: Monitors the pH value of the acid solution at the bottom of the tank in real time. When the pH value reaches 5.5-6.0, it automatically discharges the lithium-rich back-extraction solution and replenishes fresh hydrochloric acid.

[0066] In step S2 of this embodiment of the invention, the inlet pressure of the first-stage cyclone separation module is controlled to be 0.15-0.35 MPa to achieve rapid and effective separation of the oil and water phases.

[0067] In step S4 provided in this embodiment of the invention, the volume flow ratio of oil phase to acid is controlled to be 8:1 to 15:1, and the countercurrent contact time is 8-20 minutes.

[0068] In step S6 of this embodiment of the invention, the discharged lithium-rich back-extraction liquid is transported to the subsequent evaporation and crystallization unit to produce lithium chloride or lithium carbonate products.

[0069] Example 1 (System Overall Structure)

[0070] The offshore oil production system based on multi-core tube hydrocyclone separation is deployed on an offshore oil production platform. Raw water, after being treated by a pretreatment unit through precision filtration and an oil removal membrane assembly, enters a static mixer where it is mixed with the regenerated oil phase at a volume ratio of 2:1. The mixture then flows into a multi-core tube hydrocyclone separation module, which contains six parallel micro-hydrocyclones. The inlet of each hydrocyclone is tangentially arranged to create a strong swirling field, achieving efficient oil-water separation.

[0071] The upper oil phase is fed into the back-extraction mixer via a collection pipe, where it is mixed with a 2 mol / L hydrochloric acid solution. The mixture is then separated from the lithium-loaded acid solution by a back-extraction separator. The regenerated oil phase flows into an oil phase regeneration tank, where a pH sensor monitors the liquid phase acidity in real time. When the pH rises to 4.0, the PLC automatically starts the circulation pump to drain the liquid and replenish the acid solution, achieving closed-loop operation of the system.

[0072] Example 2 (Multi-core tube cyclone separation module)

[0073] The outer shell of the multi-core tube cyclone separator is a corrosion-resistant stainless steel cylinder, 200 mm in diameter and 800 mm in length, containing nine parallel cyclone tubes. Each tube inlet adopts a tangential feeding structure with a cone angle of 20 degrees and a length of 150 mm. The outlets are divided into an upper oil phase outlet and a lower water phase outlet, which are collected in the top and bottom cavities, respectively.

[0074] During operation, the mixture enters the feed chamber through the main inlet, forming multiple independent swirling units. The oil phase rises and collects along the central axis under centrifugal force, while the water phase sinks and is discharged along the wall. This parallel module can complete oil-water phase separation within 2 seconds, with an oil phase purity exceeding 98%, meeting the requirements of the lithium extraction process.

[0075] Example 3 (Back-extraction and regeneration module)

[0076] The back-extraction mixer uses a static mixing tube with corrugated mixing elements to maximize the contact area between the acid solution and the lithium-rich oil phase. The mixture then flows into the second-stage multi-core tube cyclone separator to complete the separation of the acid solution and the oil phase.

[0077] The acid outlet at the bottom of the stripping separator leads to a lithium-rich stripping solution storage tank, while the oil phase at the top is pumped back to the oil phase regeneration tank. A gas vent and a level sensor are installed at the top of the regeneration tank, and a PLC system precisely controls the acid consumption to achieve long-term continuous regeneration.

[0078] Example 4 (Control System)

[0079] The PLC controller is set to a pH threshold range of 3.8 to 4.2. The pH sensor signal is input to the PLC via an analog-to-digital converter. The control logic includes time delay and hysteresis protection. When the pH is higher than 4.0 twice consecutively, a drainage action is triggered to prevent false triggering.

[0080] After the circulation pump starts, it discharges the lithium-rich liquid in the tank to the collection tank, and at the same time, it activates the acid solenoid valve to replenish the liquid. The PLC display shows the pH value, pump operating status and system flow rate in real time, realizing fully automatic unattended control.

[0081] Example 5 (Lithium Extraction Method and Process)

[0082] The experiment was conducted using the method described in claim 7. The pretreated water sample was production water containing 10 mg / L of oil and 20 mg / L of lithium ions. After mixing, cyclone separation, and back-extraction processes, the lithium ion concentration in the acid solution reached 180 mg / L, and the extraction rate exceeded 90%.

[0083] Experiments show that the introduction of the multi-core tube cyclone separation module significantly improves the separation rate and phase stability. The system maintains stable separation performance after 72 hours of continuous operation, and the oil phase circulation loss is less than 1%.

[0084] Example 6 (Optimization of a Single Swirl Tube)

[0085] The hydrocyclone structure was optimized to address the density differences in water samples from different sea areas. When the water phase density is 1020 kg / m³ and the oil phase density is 890 kg / m³, the single-pipe inlet diameter is designed to be 8 mm and the cone angle to be 15 degrees, which can achieve optimal separation.

[0086] Under this structure, the separation pressure loss is 0.12 MPa, the unit energy consumption is reduced by about 20%, and the oil phase recovery efficiency is stable at over 98%, proving that this structural design has significant energy-saving and separation advantages.

[0087] Example 7 (Extraction conditions and mass transfer parameters)

[0088] During the back-extraction stage, hydrochloric acid at concentrations of 1 to 3 mol / L is used for back-extraction, and the reaction time is controlled within 60 seconds. The back-extraction rate increases significantly with higher acid concentrations, but concentrations exceeding 3 mol / L lead to a decrease in oil phase stability.

[0089] Therefore, 2 mol / L was selected as the optimal operating condition. Under this condition, the lithium ion concentration in the acid solution increased the most, and the relative density and viscosity of the oil phase remained stable, allowing for reuse more than 20 times.

[0090] Example 8 (Automation Integration System)

[0091] The system is integrated into a standard offshore platform modular framework, occupying an area of ​​4 square meters and a height of 1.8 meters. Each module is connected to explosion-proof cables via stainless steel conduits, and the PLC control cabinet is installed inside a protective enclosure.

[0092] Once the system is in operation, it can automatically complete the entire process of sampling, separation, back-extraction, and regeneration. The operating data is uploaded to the control center through a remote monitoring system, realizing unmanned management and status alarms. The overall lithium extraction energy consumption is less than 0.3 kWh per cubic meter.

[0093] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A water-based lithium extraction system for offshore platforms based on cyclone separation, characterized in that, include: Mixing extraction tank, acid regeneration tank, and PLC control system; The mixing extraction tank is a vertical tank, which integrates a mixing extraction zone, a primary cyclone separation module, and a secondary cyclone separation module as internal components from bottom to top. The mixing extraction tank is equipped with a production water inlet and an extractant inlet at the bottom, an oil phase outlet at the top, and an aqueous phase outlet at the side or bottom. The mixing and extraction zone is located at the bottom of the tank and is used to fully mix the production water and the extractant. The primary hydrocyclone separation module is located above the mixing and extraction zone and includes a liquid distributor and 3-12 hydrocyclones connected in parallel. The inlet of the liquid distributor is connected to the mixing and extraction zone, and its outlet is connected to the inlet of each hydrocyclone in a one-to-one correspondence. The secondary cyclone separation module is located above the primary cyclone separation module. Its inlet is connected to the oil phase outlet of the primary cyclone separation module, its oil phase outlet is connected to the oil phase outlet of the mixing extraction tank, and its aqueous phase outlet is connected to the inner cavity of the tank. The oil phase outlet of the mixing extraction tank is connected to the oil phase inlet at the bottom of the acid regeneration tank via a pipeline, and comes into countercurrent contact with the acid to perform ion exchange; The acid regeneration tank is equipped with an acid circulation and distribution system, an oil phase distributor, integrated separation internal components, a pH sensor, a lithium-rich liquid discharge port, and an acid replenishment port. The regenerated oil phase outlet at the top is connected back to the extractant inlet of the mixing extraction tank via a pipeline. The PLC control system is connected to the control valves on the pH sensor, the lithium-rich liquid discharge port, and the acid replenishment port.

2. The system as described in claim 1, characterized in that, The liquid distributor of the primary cyclone separation module is a porous tube or annular tube structure, and the sum of its total outlet orifice areas is less than the cross-sectional area of ​​the inlet pipe to ensure uniform pressure distribution.

3. The system as described in claim 1, characterized in that, The secondary cyclone separation module is a coalescing hydrocyclone assembly, in which the inner wall of the cone section or the surface of the central rod of each hydrocyclone is coated with an oleophilic and hydrophobic material layer.

4. The system according to claim 1, characterized in that, The integrated separation internal components in the acid regeneration tank are a cyclone plate group or a small hydrocyclone group, which are set above the countercurrent contact zone to quickly separate the oil-water mixture formed after back-extraction.

5. The system according to claim 1, characterized in that, The mixing and extraction zone is equipped with a static mixing unit or a dynamic stirrer.

6. The system according to claim 1, characterized in that, The PLC control system is configured to automatically open the discharge valve to discharge lithium-rich liquid and replenish hydrochloric acid with a concentration of 1-3 mol / L when the pH value in the acid regeneration tank is detected to rise to 5.5-6.

0.

7. A method for lithium extraction using the system described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Marine platform production water with an oil content reduced to below 5-10 ppm is pumped into the mixing extraction zone at the bottom of the mixing extraction tank along with recycled extractant for deep mixing extraction; S2: The extracted oil-water mixture enters the first-stage hydrocyclone separation module upwards, and is evenly distributed to each hydrocyclone by the liquid distributor for primary centrifugal separation; the separated aqueous phase is discharged downwards from the bottom water phase outlet of the tank, and the oil phase enters the second-stage hydrocyclone separation module upwards. S3: The oil phase undergoes deep separation in the two-stage cyclone separation module to further remove the entrained water phase, and the purified lithium-rich oil phase is discharged from the oil phase outlet at the top of the tank. S4: The lithium-rich oil phase enters from the bottom of the acid regeneration tank, is dispersed by the distributor, and flows upward to come into countercurrent contact with the 1-3 mol / L hydrochloric acid solution in the tank to carry out the back-extraction reaction; S5: After back-extraction, the mixture is rapidly separated in the integrated separation internal components inside the tank. The regenerated oil phase is exported from the top of the tank and returned to the mixing extraction tank for recycling, while the lithium acid-containing liquid is retained at the bottom of the tank. S6: Monitors the pH value of the acid solution at the bottom of the tank in real time. When the pH value reaches 5.5-6.0, it automatically discharges the lithium-rich back-extraction solution and replenishes fresh hydrochloric acid.

8. The method according to claim 7, characterized in that, In step S2, the inlet pressure of the first-stage cyclone separation module is controlled to be 0.15-0.35 MPa to achieve rapid and effective separation of the oil and water phases.

9. The method according to claim 7, characterized in that, In step S4, the volumetric flow rate ratio of the oil phase to the acid is controlled to be 8:1 to 15:1, and the countercurrent contact time is 8-20 minutes.

10. The method according to claim 7, characterized in that, In step S6, the discharged lithium-rich back-extraction solution is transported to the subsequent evaporation and crystallization unit to produce lithium chloride or lithium carbonate products.

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