A method for recovering rare earth elements by solution extraction

Abstract

The invention discloses a method for recovering rare earth elements by solution extraction, and relates to the technical field of rare earth extraction. The method comprises the following steps: injecting a solution containing rare earth elements into a first mixing chamber for stirring; mixing an extractant P507 with a diluent, and then injecting the solution into a second mixing chamber through a pipeline, and the second mixing chamber stirs and mixes the solution containing rare earth elements and the extractant P507 mixed with the diluent to form a mixed solution; the mixed solution passes through a grid fence between the second mixing chamber and a clarifying chamber to filter impurities and foam, and then enters the clarifying chamber; the mixed solution entering the clarifying chamber, after static stratification, forms an upper layer of a rare earth-loaded organic phase, a middle layer of a water phase, and a lower layer of a raffinate phase; the water phase in the middle layer of the clarifying chamber will enter the bottom of the second mixing chamber through a pipeline, and the raffinate phase in the lower layer of the clarifying chamber will enter the bottom of the first mixing chamber through a pipeline; the rare earth-loaded organic phase is finally extracted and collected from the extractant outlet in the upper cover at the rear of the clarifying chamber.

Description

Technical Field

[0001] The invention relates to the technical field of rare earth extraction, and in particular to a method for recovering rare earth elements by solution extraction. Background Art

[0002] Hydrometallurgy is often used in industry to recover rare earths and precious metals. Hydrometallurgy includes leaching and reprocessing of the leachate, including ion exchange, chemical precipitation, component adsorption and solvent extraction, among which solvent extraction is widely used because of its good separation and enrichment effects, high selectivity and regeneration ability. However, this field still faces many problems, including improving the selectivity of the extractant, enhancing the recovery rate of rare earth elements, reducing environmental pollution and improving the economy of the entire extraction process.

[0003] After extensive analysis of the extraction process research based on the existing technology, it was found that the improvement of the extraction process, the selection of the extraction agent, and the internal structure of the extraction equipment have an important influence on the fluid flow and the mixing of the feed liquid.

[0004] Therefore, in view of this, the inventors have studied and improved the existing technology and its deficiencies, and provided a method for recovering rare earth elements by solution extraction, in order to achieve a more practical purpose. Summary of the invention

[0005] In order to solve the problems mentioned in the above background technology, the present invention provides a method for recovering rare earth elements by solution extraction.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for recovering rare earth elements by solution extraction comprises the following steps:

[0008] S1, injecting a solution containing rare earth elements into a first mixing chamber of an extraction device, and stirring the solution containing rare earth elements by a first stirring mechanism of the first mixing chamber;

[0009] S2, after the extractant P507 is mixed with the diluent, it is injected from the bottom of the second mixing chamber through a pipeline, after the extractant P507 is mixed with the diluent, it is injected from the bottom of the second mixing chamber through a pipeline, and the second stirring mechanism of the second mixing chamber stirs and mixes the inflowing rare earth element-containing solution with the extractant P507 mixed with the diluent to form a mixed solution;

[0010] S3, the mixed liquid passes through the grid fence between the second mixing chamber and the clarifying chamber to filter out impurities and foam, and then enters the clarifying chamber;

[0011] S4, the mixed liquid entering the clarification chamber is placed and separated into an upper layer of an organic phase loaded with rare earth, a middle layer of an aqueous phase, and a lower layer of a raffinate phase;

[0012] S5, the water phase in the middle layer of the clarification chamber will enter the bottom of the second mixing chamber through the pipeline, and the raffinate phase in the lower layer of the clarification chamber will enter the bottom of the first mixing chamber through the pipeline;

[0013] S6. The rare earth-loaded organic phase passes through the overflow channel on the upper part of the overflow baffle at the rear of the clarification chamber and enters the rear side of the overflow baffle, and is finally extracted and collected from the extraction liquid outlet in the upper cover at the rear of the clarification chamber.

[0014] Preferably, the first stirring mechanism and the second stirring mechanism are directly driven by gear meshing, the transmission gear of the first stirring mechanism is driven by a motor, and the gear ratio of the transmission gear of the first stirring mechanism to the transmission gear of the second stirring mechanism is 1:2.

[0015] Preferably, in step S2, a neutral phosphorus extractant is injected from the bottom of the second mixing chamber, and the ratio of the extractant P507 to the neutral phosphorus extractant is 4:3.

[0016] Preferably, the raffinate phase in the lower layer of the clarification chamber in step S5 can also be extracted into a container through a pipeline, and then the extractant P204, sulfonated kerosene and tributyl phosphate are added to the container.

[0017] Preferably, heating strips are embedded in the surrounding inner walls of the clarification chamber at the water phase position.

[0018] Preferably, the first mixing chamber and the second mixing chamber are connected, and baffles are arranged in parallel and staggered manner above and below at the boundary of the connection, and there is a distance between the two baffles.

[0019] Preferably, four end plates are vertically arranged around the inner wall of the second mixing chamber, and the height of the end plates is consistent with the height of the liquid level in the second mixing chamber.

[0020] Preferably, the effective liquid level height of the first mixing chamber and the second mixing chamber is 525 mm, and the stirring paddles used by the first stirring mechanism and the second stirring mechanism are double-layer impeller structures with a paddle diameter of 140 mm.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. In the present invention, the rare earth element-containing solution flowing out of the first mixing chamber is mixed with the diluent and the extractant P507 by the second stirring mechanism of the second mixing chamber, and then a neutral phosphorus extractant is injected from the bottom of the second mixing chamber to form a mixed solution. By adding the neutral phosphorus extractant, it can be used in conjunction with the extractant P507 to produce synergistic extraction, thereby accelerating the extraction reaction. The system can dissolve the formed third phase to prevent the formation of the third phase.

[0023] 2. The present invention improves the internal structure of the extraction equipment, adopts the arrangement of the first mixing chamber and the second mixing chamber in series, and arranges pipelines between the first mixing chamber, the second mixing chamber and the clarification chamber to recycle the water phase and the raffinate phase, thereby reducing resource waste. The recovery rate of rare earth elements is improved, and the production cost is reduced. At the same time, the flow rate of the solution containing rare earth elements entering the first mixing chamber is automatically controlled by the up and down floating of the floating plate, which can ensure that the rare earth ions are fully in contact with the extractant and improve the extraction efficiency. The appropriate flow rate can ensure the mass transfer efficiency in the mixing chamber, and avoid insufficient mixing due to too fast or reduced production efficiency due to too slow. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is a flow chart of a method for recovering rare earth elements by solution extraction according to the present invention;

[0026] Figure 2 is a first cross-sectional view of the extraction device of the present invention;

[0027] Figure 3 is a second cross-sectional view of the extraction device of the present invention;

[0028] Figure 4 It is a cross-sectional view of the valve plate position of the extraction device of the present invention.

[0029] In the figure: 1, clarification chamber; 2, first mixing chamber; 3, second mixing chamber; 4, pipeline; 5, floating plate; 6, hollow rod; 7, valve plate; 8, overflow baffle; 9, pipeline flow port; 10, valve plate mounting seat; 11, solution inlet. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0032] Embodiment 1: A method for recovering rare earth elements by solution extraction, comprising the following steps:

[0033] S1, injecting a solution containing rare earth elements into a first mixing chamber of an extraction device, stirring the solution containing rare earth elements by a first stirring mechanism of the first mixing chamber, so that the rare earth elements are evenly distributed in the solution, in preparation for a subsequent extraction process;

[0034] S2, after the extractant P507 is mixed with the diluent, it is injected from the bottom of the second mixing chamber through a pipeline. After the extractant P507 is mixed with the diluent, it is injected from the bottom of the second mixing chamber through a pipeline. The second stirring mechanism of the second mixing chamber stirs and mixes the inflowing rare earth element-containing solution with the extractant P507 mixed with the diluent to form a mixed solution. P507, as an extractant, can effectively form a complex with the rare earth element, thereby transferring it from the aqueous phase to the organic phase;

[0035] S3, after the mixed liquid passes through the grid fence between the second mixing chamber and the clarifying chamber to filter out impurities and foam, it enters the clarifying chamber. By removing solid impurities and foam in the mixed liquid, the liquid components in the clarifying chamber are kept pure, which is beneficial to the subsequent stratification and extraction. This improves the quality of the extract and reduces the impact of impurities on the extraction effect;

[0036] S4, the mixed liquid entering the clarification chamber is placed and stratified to form an upper layer of rare earth-loaded organic phase, a middle layer of water phase, and a lower layer of raffinate phase. The density difference between the different phases is utilized to achieve stratification through gravity sedimentation, thereby achieving effective separation of rare earth elements, preparing for the next step of collection and purification;

[0037] S5, the water phase in the middle layer of the clarification chamber will enter the bottom of the second mixing chamber through the pipeline, and the raffinate phase in the lower layer of the clarification chamber will enter the bottom of the first mixing chamber through the pipeline. This process realizes the recycling of the water phase and the raffinate phase, reduces resource waste, improves the recovery rate of rare earth elements, and reduces production costs;

[0038] S6, the rare earth-loaded organic phase passes through the overflow channel on the upper part of the overflow baffle at the rear of the clarification chamber and enters the rear side of the overflow baffle, and is finally extracted and collected from the extraction liquid outlet in the upper cover at the rear of the clarification chamber, and the organic phase rich in rare earth elements is collected for subsequent purification and treatment;

[0039] S7. Stripping the collected organic phase rich in rare earth elements to obtain a stripping solution, then introducing the stripping solution into a precipitation tank, adjusting the pH value to precipitate the rare earth ions, and then filtering and washing the precipitate.

[0040] Embodiment 2: A method for recovering rare earth elements by solution extraction, comprising the following steps:

[0041] S1, injecting a solution containing rare earth elements into a first mixing chamber of an extraction device, stirring the solution containing rare earth elements by a first stirring mechanism of the first mixing chamber, so that the rare earth elements are evenly distributed in the solution, in preparation for subsequent extraction;

[0042] S2. After the extractant P507 is mixed with the diluent, it is injected from the bottom of the second mixing chamber through a pipeline. The second stirring mechanism of the second mixing chamber stirs and mixes the inflowing rare earth element-containing solution and the extractant P507 mixed with the diluent, and then the neutral phosphorus extractant is injected from the bottom of the second mixing chamber to form a mixed solution, wherein the ratio of the extractant P507 to the neutral phosphorus extractant is 4:3. P507, as an extractant, can effectively form a complex with the rare earth element, thereby transferring it from the aqueous phase to the organic phase. The added neutral phosphorus extractant can be used in conjunction with the extractant P507 to produce synergistic extraction, thereby accelerating the extraction reaction and forming a more stable extractant. The neutral phosphorus extractant can accelerate the generation of hydrogen bonds between the extractant P507 and the metal ions, promote the combination between the metal ions and the extractant, and the neutral phosphorus extractant can also directly generate a more solid coordination bond with the metal ions. Here, the extractant itself participates in the extraction reaction in the form of neutral molecules, and the extracted metal is also extracted in the form of neutral compounds. Therefore, it can also be adsorbed on the extractant based on the intermolecular force to play a synergistic role. At the same time, in addition to synergistic extraction, the neutral phosphorus extractant and the extractant P507 can also dissolve the third phase formed during the extraction process to prevent the formation of the third phase;

[0043] S3, after the mixed liquid passes through the grid fence between the second mixing chamber and the clarifying chamber to filter out impurities and foam, it enters the clarifying chamber. By removing solid impurities and foam in the mixed liquid, the liquid components in the clarifying chamber are kept pure, which is beneficial to the subsequent stratification and extraction. This improves the quality of the extract and reduces the impact of impurities on the extraction effect;

[0044] S4, the mixed liquid entering the clarification chamber is placed and stratified to form an upper layer of rare earth-loaded organic phase, a middle layer of water phase, and a lower layer of raffinate phase. The density difference between the different phases is utilized to achieve stratification through gravity sedimentation, thereby achieving effective separation of rare earth elements, preparing for the next step of collection and purification;

[0045] S5, the water phase in the middle layer of the clarification chamber will enter the bottom of the second mixing chamber through the pipeline, and the raffinate phase in the lower layer of the clarification chamber will enter the bottom of the first mixing chamber through the pipeline. This process realizes the recycling of the water phase and the raffinate phase, reduces resource waste, improves the recovery rate of rare earth elements, and reduces production costs;

[0046] S6. The rare earth-loaded organic phase passes through the overflow channel on the upper part of the overflow baffle at the rear of the clarification chamber and enters the rear side of the overflow baffle, and is finally extracted and collected from the extraction liquid outlet in the upper cover at the rear of the clarification chamber, and the organic phase rich in rare earth elements is collected for subsequent purification and treatment.

[0047] S7. Stripping the collected organic phase rich in rare earth elements to obtain a stripping solution, then introducing the stripping solution into a precipitation tank, adjusting the pH value to precipitate the rare earth ions, and then filtering and washing the precipitate.

[0048] Embodiment 3: A method for recovering rare earth elements by solution extraction, comprising the following steps:

[0049] S1, injecting a solution containing rare earth elements into a first mixing chamber of an extraction device, stirring the solution containing rare earth elements by a first stirring mechanism of the first mixing chamber, so that the rare earth elements are evenly distributed in the solution, in preparation for a subsequent extraction process;

[0050] S2, after the extractant P507 is mixed with the diluent, it is injected from the bottom of the second mixing chamber through a pipeline. After the extractant P507 is mixed with the diluent, it is injected from the bottom of the second mixing chamber through a pipeline. The second stirring mechanism of the second mixing chamber stirs and mixes the inflowing rare earth element-containing solution with the extractant P507 mixed with the diluent to form a mixed solution. P507, as an extractant, can effectively form a complex with the rare earth element, thereby transferring it from the aqueous phase to the organic phase;

[0051] S3, after the mixed liquid passes through the grid fence between the second mixing chamber and the clarifying chamber to filter out impurities and foam, it enters the clarifying chamber. By removing solid impurities and foam in the mixed liquid, the liquid components in the clarifying chamber are kept pure, which is beneficial to the subsequent stratification and extraction. This improves the quality of the extract and reduces the impact of impurities on the extraction effect;

[0052] S4, the mixed liquid entering the clarification chamber is placed and stratified to form an upper layer of rare earth-loaded organic phase, a middle layer of water phase, and a lower layer of raffinate phase. The density difference between the different phases is utilized to achieve stratification through gravity sedimentation, thereby achieving effective separation of rare earth elements, preparing for the next step of collection and purification;

[0053] S5, the water phase in the middle layer of the clarification chamber will enter the bottom of the second mixing chamber through a pipeline, and the raffinate phase in the lower layer of the clarification chamber will be extracted into a container through a pipeline, and then the extractant P204, sulfonated kerosene and tributyl phosphate are added to the container, and the extractant and the raffinate phase are fully mixed by stirring to promote further extraction of rare earth elements, thereby obtaining extracted organic matter and water phase, and the extracted organic matter is stripped to obtain stripping liquid;

[0054] S6. The rare earth-loaded organic phase passes through the overflow channel on the upper part of the overflow baffle at the rear of the clarification chamber and enters the rear side of the overflow baffle, and is finally extracted and collected from the extraction liquid outlet in the upper cover at the rear of the clarification chamber, and the organic phase rich in rare earth elements is collected for subsequent purification and treatment.

[0055] S7, stripping the collected rare earth element-rich organic phase to obtain a stripping solution, then introducing the stripping solution and the stripping solution in step S5 into a precipitation tank, adjusting the pH value to precipitate the rare earth ions, and then filtering and washing the precipitate.

[0056] Embodiment 4: A method for recovering rare earth elements by solution extraction, wherein the method for extracting rare earths from a rare earth solution is implemented by an extraction device, wherein the extraction device comprises a first mixing chamber 2, a second mixing chamber 3, a clarifying chamber 1 and a pipeline 4, wherein the first mixing chamber 2 and the second mixing chamber 3 are located in a chamber and have a liquid-connected channel, wherein two baffles are arranged in parallel and staggered manner at the boundary where the first mixing chamber 2 and the second mixing chamber 3 are connected, wherein the design of the baffles helps to control the flow of the mixed solution, ensure sufficient mixing, and reduce direct short circuits, wherein the clarifying chamber 1 is adjacent to the side of the second mixing chamber 3, and the clarifying chamber 1 is fixed with a A grid fence, an overflow plate is provided behind the grid fence, the mixed liquid in the second mixing chamber 3 enters the clarification chamber 1, and the overflow plate is provided at the entrance of the mixed liquid to control the liquid level and prevent droplet entrainment, thereby reducing cross contamination between the two phases and helping to maintain a clear interface when the two phases are separated. An overflow baffle 8 is provided at the rear of the clarification chamber 1, and pipes 4 are respectively provided between the first mixing chamber 2 and the second mixing chamber 3 and the clarification chamber 1. The pipe 4 between the second mixing chamber 3 and the clarification chamber 1 will introduce the water phase in the middle layer of the clarification chamber 1 into the second mixing chamber 3. At the same time, the pipe 4 will also absorb the foam generated in the water phase, thereby reducing the interface miscibility and clarification time and improving the extraction efficiency.

[0057] The first mixing chamber 2 and the second mixing chamber 3 are respectively provided with a first stirring mechanism and a second stirring mechanism, and the first stirring mechanism and the second stirring mechanism are driven by gear meshing. The transmission gear of the first stirring mechanism is driven by a motor, and the gear ratio of the transmission gear of the first stirring mechanism to the transmission gear of the second stirring mechanism is 1:2. The stirring paddles used by the first stirring mechanism and the second stirring mechanism are double-layer impeller structures with a paddle diameter of 140 mm. The stirring shaft speed of the first stirring mechanism is 300 r / min. The stirring paddles and speed of the double-layer impeller structure here help to achieve a good mixing effect and avoid the formation of emulsions caused by excessive shear force. The inner wall of the second mixing chamber 3 is vertically provided with 4 end plates, and the height of the end plates is consistent with the liquid level height of the second mixing chamber 3, which helps to limit the radial movement of the liquid and promote the axial mixing and separation of the two phases. The inner walls around the water phase position in the clarification chamber 1 are embedded with heating strips. The heating effect of the heating strips will reduce the viscosity of the water phase, increase the aggregation between droplets, and promote the merging of droplets, thereby reducing emulsification. A floating plate 5 is provided in the clarification chamber 1, and the floating plate 5 controls the position of the valve plate 7 in the pipeline 4 through the hollow rod 6, thereby controlling the path area of ​​the solution containing rare earth elements entering the first mixing chamber 2, thereby realizing the flow control of the solution containing rare earth elements entering the first mixing chamber 2. When the liquid level in the clarification chamber 1 exceeds the set height, the floating plate 5 drives the hollow rod 6 to pull up the valve plate 7, and the lifting of the valve plate 7 will reduce the path area of ​​the pipeline 4, thereby reducing the flow rate of the solution containing rare earth elements entering the first mixing chamber 2. When the liquid level in the clarification chamber 1 is lower than the set height, the floating plate 5 drives the hollow rod 6 to pull up the valve plate 7. The lifting of the valve plate 7 will reduce the path area of ​​the pipeline 4, thereby reducing the flow rate of the solution containing rare earth elements entering the first mixing chamber 2. When the flow rate of the rare earth element solution enters the first mixing chamber 2, the float plate 5 and the hollow rod 6 descend, and the valve plate also descends, thereby increasing the diameter area of ​​the pipeline 4 and increasing the flow rate of the solution containing rare earth elements entering the first mixing chamber 2, wherein the valve plate 7 is vertically installed in the valve plate mounting seat 10, and the hollow rod 6 passes through the upper end of the valve plate mounting seat 10 and is connected to the valve plate 7, and the valve plate 7 is used to control the flow area of ​​the pipeline flow port 9. The right side of the pipeline flow port 9 is provided with a solution inlet 11 for the solution containing rare earth elements to enter, and the pipeline 4 for the downstream raffinate phase of the lower layer of the clarification chamber is connected to the solution inlet 11.

[0058] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for recovering rare earth elements by solution extraction, characterized in that: The following steps are involved: S1, injecting a solution containing rare earth elements into a first mixing chamber of an extraction device, and stirring the solution containing rare earth elements by a first stirring mechanism of the first mixing chamber; S2, after the extractant P507 is mixed with the diluent, it is injected from the bottom of the second mixing chamber through the pipeline, and the second stirring mechanism of the second mixing chamber stirs and mixes the inflowing rare earth element-containing solution with the extractant P507 mixed with the diluent to form a mixed solution; S3, the mixed liquid passes through the grid fence between the second mixing chamber and the clarifying chamber to filter out impurities and foam, and then enters the clarifying chamber; S4, the mixed liquid entering the clarification chamber forms an upper layer of rare earth-loaded organic phase, a middle layer of water phase, and a lower layer of raffinate phase after static stratification. Pipes are respectively provided between the first mixing chamber, the second mixing chamber and the clarification chamber. The pipe between the second mixing chamber and the clarification chamber will guide the water phase in the middle layer of the clarification chamber into the second mixing chamber; S5. The water phase in the middle layer of the clarification chamber will enter the bottom of the second mixing chamber through the pipeline, and the raffinate phase in the lower layer of the clarification chamber will enter the bottom of the first mixing chamber through the pipeline. A floating plate is provided in the clarification chamber. The floating plate controls the position of the valve plate in the pipeline through a hollow rod, thereby controlling the flow area of ​​the solution containing rare earth elements entering the first mixing chamber. When the liquid level in the clarification chamber exceeds the set height, the floating plate drives the hollow rod to pull up the valve plate. The lifting of the valve plate will reduce the flow area of ​​the pipeline, thereby reducing the solution containing rare earth elements entering the first mixing chamber. The flow rate of a mixing chamber is controlled by the floating plate and the hollow rod. When the liquid level in the clarification chamber is lower than the set height, the floating plate and the hollow rod descend, and the valve plate also descends, thereby increasing the diameter area of ​​the pipeline and increasing the flow rate of the solution containing rare earth elements entering the first mixing chamber. The valve plate is vertically installed in the valve plate mounting seat, and the hollow rod penetrates from the upper end of the valve plate mounting seat and is connected to the valve plate. The valve plate is used to control the flow area of ​​the pipeline flow port. The right side of the pipeline flow port is provided with a solution inlet for the solution containing rare earth elements to enter. The pipeline for the downstream raffinate phase of the lower layer of the clarification chamber is connected to the solution inlet. S6. The rare earth-loaded organic phase passes through the overflow channel on the upper part of the overflow baffle at the rear of the clarification chamber and enters the rear side of the overflow baffle, and is finally extracted and collected from the extraction liquid outlet in the upper cover at the rear of the clarification chamber.

2. The method for recovering rare earth elements by solution extraction according to claim 1, characterized in that: The first stirring mechanism and the second stirring mechanism are directly driven by gear meshing. The transmission gear of the first stirring mechanism is driven by a motor, and the gear ratio of the transmission gear of the first stirring mechanism to the transmission gear of the second stirring mechanism is 1:

2.

3. The method for recovering rare earth elements by solution extraction according to claim 1, characterized in that: In the step S2, a neutral phosphorus extractant is injected from the bottom of the second mixing chamber, and the ratio of the extractant P507 to the neutral phosphorus extractant is 4:

3.

4. The method for recovering rare earth elements by solution extraction according to claim 1, characterized in that: The raffinate phase in the lower layer of the clarification chamber in step S5 can also be extracted into a container through a pipeline, and then the extractant P204, sulfonated kerosene and tributyl phosphate are added to the container.

5. The method for recovering rare earth elements by solution extraction according to claim 1, characterized in that: Heating strips are embedded in the inner walls around the clarification chamber at the water phase position.

6. The method for recovering rare earth elements by solution extraction according to claim 1, characterized in that: The first mixing chamber and the second mixing chamber are connected, and baffles are arranged in parallel and staggered manner at the boundary of the connection, and there is a distance between the two baffles.

7. The method for recovering rare earth elements by solution extraction according to claim 1, characterized in that: The effective liquid level height of the first mixing chamber and the second mixing chamber is 525 mm, and the stirring paddles used by the first stirring mechanism and the second stirring mechanism are double-layer impeller structures with a paddle diameter of 140 mm.

8. The method for recovering rare earth elements by solution extraction according to claim 1, characterized in that: Four end plates are vertically arranged around the inner wall of the second mixing chamber, and the height of the end plates is consistent with the height of the liquid level in the second mixing chamber.

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