Device and method for extracting and separating rare earth
Through liquid film preparation and high-pressure electrostatic separation technology, the problems of high chemical usage rate and low separation efficiency in rare earth element recycling are solved, and selective migration and economic recovery of high-purity rare earths are achieved.
Patent Information
- Application Number
- CN202510801759.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-16
- Publication Date
- 2025-08-22
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The existing rare earth element recycling methods have problems such as high chemical usage, low selectivity, high cost of generating large amounts of waste and high temperature furnaces. The separation efficiency of conventional solvent extraction processes is limited, and multiple steps and third phase formation is required.
Liquid film preparation technology is adopted to form a stable emulsion film through high-shear emulsification equipment, and selective migration and desorption are achieved by utilizing the complexing ability of rare earths and carriers. The organic phase and the rare earth-rich internal phase are separated by high-voltage electrostatic method or centrifugal method, the organic phase effluent rate is controlled, and the organic phase is recycled to reduce costs.
The recycling of high-purity rare earth elements is achieved, and the rare earth concentration can reach more than 50 g/L, which reduces the organic phase loss rate to below 1%, reduces environmental pollution, and improves separation efficiency and economicality.
Smart Images
Figure CN120519718A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of extracting and separating rare earths, and in particular to a device and method for extracting and separating rare earths. Background Art
[0002] The present invention relates to a method for recovering rare earth elements, and more particularly, to membrane-assisted solvent extraction for recovering rare earth elements from post-consumer and other end-of-life products. Rare earth elements play an increasingly important role in the development of green energy and high-tech industries. For example, demand for rare earth elements has grown with increasing use in permanent magnets for motors, rechargeable batteries for hybrid electric vehicles, catalysts for petroleum refining, phosphors for flat-panel displays, and generators for wind turbines.
[0003] Current recovery methods for rare earth elements include hydrometallurgy, pyrometallurgy, gas phase extraction and solvent extraction. Of these methods, hydrometallurgy is the most commonly used recovery method for rare earth elements in permanent magnets. For example, permanent magnets can be dissolved in strong acids such as sulfuric acid, hydrochloric acid, phosphoric acid and nitric acid, and rare earth elements can be selectively precipitated as double salts of sulfates, oxalates and fluorides. However, the main problems with hydrometallurgical processes are the high usage of chemicals, low selectivity due to the co-extraction of non-rare earth elements, and the generation of large amounts of waste. Rare earth elements can also be recovered by pyrometallurgical processes, including remelting of metallic transition metals or liquid metal extraction. However, this method causes the formation of slag and the loss of a large amount of rare earth elements due to the carbon and oxygen content in the waste. In addition, the pyrometallurgical process requires further separation of the recovered rare earth element mixture and high investment costs for high-temperature furnaces; gas phase extraction has also been proposed for the recovery of rare earth elements. Gas phase extraction involves the separation of rare earth elements based on volatility differences, including the use of In the flow Chlorination with CO and carbochlorination. However, this method produces highly corrosive aluminum chloride and is accompanied by the formation of hydrogen chloride gas. Solvent extraction is another method for recovering rare earth elements by exploiting the different solubilities of solutes in two immiscible liquids. For example, this method effectively extracts Pr and Nd using 10% saponified Cyanex 272 (bis(2,4,4-trimethylpentyl)phosphinic acid) and 0.5 M TBP (tributyl phosphate). However, in conventional solvent extraction processes, separation is limited by material equilibrium, requiring a contact time sufficient for one phase to disperse in the other immiscible phase. In addition, this equilibrium-based separation process performs extraction and stripping in two separate steps, and requires that loading, flooding, third phase formation, and extractant loss be considered as part of the overall recovery process.
[0004] Therefore, there remains a need for an improved system and method for recovering rare earth elements. In particular, there remains a need for improved methods for recovering rare earth elements from post-consumer and other end-of-life products while reducing environmental impact. Summary of the Invention
[0005] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid blurring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.
[0006] In view of the above-mentioned problems and / or the problems existing in the existing device and method for extracting and separating rare earths, the present invention is proposed.
[0007] Therefore, the purpose of the present invention is to provide a device and method for extracting and separating rare earths. First, a liquid membrane is prepared, and a matrix, a mobile carrier and a surfactant are mixed in proportion. A stable emulsion liquid membrane is formed by a high-shear emulsification device. Then, the rare earth raw material and the acidic solution are mixed to form a rare earth feed liquid. Then, the emulsion liquid membrane and the rare earth feed liquid are injected into an extraction kettle. The rare earth ions form a complex with the mobile carrier on the outer surface of the membrane and diffuse through the liquid membrane to the inner phase interface of the acidic desorbent in step 1. The selective migration of the target rare earth is achieved by utilizing the difference in the complexing ability of different rare earths and carriers. The rare earth complex reacts with the acidic solution, and the rare earth elements are desorbed into the inner phase aqueous solution, and the carrier returns to the outer phase of the membrane for reuse. The rare earth concentration in the inner phase formed by this process can reach 50 g / L or more rare earth-enriched liquid; finally, a high-voltage electrostatic method or a centrifugal method is used to destroy the emulsion membrane structure and separate the organic phase and the rare earth-rich inner phase solution; the organic phase loss rate after demulsification needs to be controlled below 1% to reduce costs, and the organic phase is recycled and circulated into the organic phase recovery barrel, so that high-purity rare earth elements can be extracted without pollution.
[0008] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions: A method for extracting and separating rare earths, comprising: 5. Liquid membrane preparation: the matrix sulfonated kerosene, the mobile carrier P204 and the surfactant acid blue 113 are mixed in proportion and formed into a stable emulsion liquid membrane through a high shear emulsification device. The membrane structure is a water-in-oil type, and the internal phase is an acidic desorbent; and the rare earth raw material and the acidic solution are mixed to form a rare earth liquid; Second, an extraction reaction, wherein the rare earth liquid is first poured into an extraction kettle, and then the emulsion film formed in the high shear emulsification equipment is dispersed in the rare earth liquid. The rare earth ions form a complex with the mobile carrier on the outer surface of the membrane and diffuse through the liquid membrane to the internal phase interface. The selective migration of the target rare earth is achieved by utilizing the difference in the complexing ability between different rare earths and the carrier; 3. Back extraction and enrichment: At the interface of the inner phase of the emulsion membrane, the rare earth complex reacts with the acidic solution, the rare earth elements are desorbed into the inner phase aqueous solution, and the carrier returns to the outer phase of the membrane for reuse; Fourth, demulsification and phase separation, using high-voltage electrostatic method or centrifugal method to destroy the emulsion membrane structure, separate the organic phase and the rare earth-rich inner phase solution; after demulsification, the organic phase is recycled and enters the organic phase recovery barrel; 5. Purify the rare earth by passing the rare earth-rich solution into the rare earth-rich inner phase solution barrel, and then precipitate, filter and burn the rare earth-rich solution.
[0009] As a preferred embodiment of the method for extracting and separating rare earths described in the present invention, after the emulsion liquid membrane is prepared, a porous support body is made. The porous support body is made of a porous support body such as polysulfone or polyacrylonitrile. When in use, the porous support body is immersed in the emulsion liquid membrane, and the liquid membrane fills the pores through capillary action to ensure the stability of the emulsion liquid membrane.
[0010] As a preferred embodiment of the method for extracting and separating rare earths described in the present invention, when the porous support is used, a surfactant, hydroxypropyl cellulose, is added to reduce the interfacial tension of the emulsion film and enhance the bonding stability between the film and the support.
[0011] As a preferred embodiment of the present invention, a device for extracting and separating rare earths comprises: A high shear emulsification device, an extraction kettle connected to the high shear emulsification device, an organic phase recovery barrel connected to the extraction kettle, and a rare earth-rich internal phase solution barrel connected to the extraction kettle, the extraction kettle is connected to a bubbling oil film extraction device, and the extraction kettle is connected to an ultrasonic generator.
[0012] As a preferred embodiment of the device for extracting and separating rare earths described in the present invention, the bubbling oil film extraction equipment accelerates the oil film extraction process in the extraction kettle, and the bubbling oil film extraction equipment is divided into a bubble generation and dispersion device and an oil-in-gas dispersed phase reactor.
[0013] As a preferred embodiment of the device for extracting and separating rare earths described in the present invention, the bubble generation and dispersion device utilizes an inert gas bubbling technique to disperse the organic extractant into bubbles coated with a thin layer of oil film, thereby increasing the mass transfer area; the oil-in-gas dispersed phase reactor utilizes an oil-in-gas microstructure design and combines the reverse flow of the aqueous phase to enhance the selective migration of rare earth ions, and is suitable for enriching solutions with a concentration of <100 mg / L.
[0014] Compared with the prior art, the present invention has the following beneficial effects: first, a liquid membrane is prepared, a matrix, a mobile carrier and a surfactant are mixed in proportion, a stable emulsion liquid membrane is formed by a high shear emulsification device, and then the rare earth raw material and the acidic solution are mixed to form a rare earth feed liquid, and then both the emulsion liquid membrane and the rare earth feed liquid are injected into the extraction kettle, the rare earth ions and the mobile carrier form a complex on the outer surface of the membrane, and the inner phase in the first step is the internal phase interface of the acidic desorbent through the liquid membrane diffusion; the selective migration of the target rare earth is achieved by utilizing the difference in the complexing ability of different rare earths and the carrier; the rare earth complex reacts with the acidic solution, the rare earth elements are desorbed into the inner phase aqueous solution, and the carrier is returned to the outer phase of the membrane for reuse; the rare earth concentration in the inner phase formed by this process can reach 50 g / L or more rare earth-enriched liquid; finally, a high-voltage electrostatic method or a centrifugal method is used to destroy the emulsion membrane structure and separate the organic phase and the rare earth-rich inner phase solution; the organic phase loss rate after demulsification needs to be controlled below 1% to reduce costs, and the organic phase is recycled and circulated into the organic phase recovery barrel, so that high-purity rare earth elements can be extracted without pollution. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort. Among them:
[0016] Figure 1 A schematic diagram of an apparatus and method for extracting and separating rare earths according to the present invention; Figure 2 This is an integrated diagram of a device and method for extracting and separating rare earths according to the present invention.
[0017] 1. High shear emulsification equipment; 2. Extraction kettle; 3. Organic phase recovery tank; 4. Rare earth-rich internal phase solution tank. DETAILED DESCRIPTION
[0018] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.
[0019] Next, the present invention is described in detail with reference to schematic diagrams. For ease of illustration, cross-sectional views of device structures may be partially enlarged and not to scale when describing the embodiments of the present invention. Furthermore, the schematic diagrams are merely illustrative and should not limit the scope of protection of the present invention. Furthermore, in actual production, three-dimensional dimensions, including length, width, and depth, should be included.
[0020] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
[0021] The present invention provides a device and method for extracting and separating rare earths. The method comprises the following steps: firstly preparing a liquid membrane, mixing a matrix, a mobile carrier and a surfactant in proportion, forming a stable emulsion liquid membrane through a high shear emulsification device, then mixing a rare earth raw material and an acidic solution into a rare earth feed liquid, and then injecting both the emulsion liquid membrane and the rare earth feed liquid into an extraction kettle. The rare earth ions form a complex with the mobile carrier on the outer surface of the membrane, and diffuse through the liquid membrane to the inner phase interface of the acidic desorbent in the inner phase of step 1; utilizing the difference in the complexing ability between different rare earths and the carrier, the selective migration of the target rare earth is achieved; the rare earth complex reacts with the acidic solution, the rare earth elements are desorbed into the inner phase aqueous solution, and the carrier is returned to the outer phase of the membrane for reuse; the rare earth concentration in the inner phase formed by this process can reach 50 g / L or more rare earth-enriched liquid; finally, a high-voltage electrostatic method or a centrifugal method is used to destroy the emulsion membrane structure and separate the organic phase and the rare earth-rich inner phase solution; the organic phase loss rate after demulsification needs to be controlled below 1% to reduce costs, and the organic phase is recycled and circulated into the organic phase recovery barrel, so that high-purity rare earth elements can be extracted without pollution.
[0022] Figure 1-Figure 2 The figure shows the overall structure of an apparatus and method for extracting and separating rare earths according to an embodiment of the present invention. Figure 1-Figure 2 , a method for extracting and separating rare earth, comprising: 1. Liquid membrane preparation: The matrix sulfonated kerosene, the mobile carrier P204, and the surfactant acid blue 113 are mixed in proportion, wherein the mass percentage of the matrix sulfonated kerosene is 70%-90%, the mass percentage of the mobile carrier P204 is 5%-20%, and the mass percentage of acid blue 113 is 1%-5%. A stable emulsion liquid membrane is formed through high shear emulsification equipment 1. The membrane structure is oil-in-water type, and the internal phase is an acidic desorbent. The rare earth raw material and the acidic solution are mixed to form a rare earth liquid. Specifically, the matrix, the mobile carrier, and the surfactant are mixed in proportion and a stable emulsion liquid membrane is formed through high shear emulsification equipment. The membrane structure is usually oil-in-water (W / O) type, and the internal phase is an acidic desorbent (such as HCl solution). The droplet size (micrometer level) can be controlled by optimizing the surfactant concentration and emulsification speed (such as 150-200 r / min), reducing the membrane breakage rate and improving the mass transfer efficiency.
[0023] Second, the extraction reaction: first, the rare earth liquid is poured into the extraction kettle 2, and then the emulsion film formed in the high-shear emulsification equipment 1 is dispersed in the rare earth liquid. The rare earth ions and the mobile carrier form a complex on the outer surface of the membrane and diffuse through the liquid film to the internal phase interface. The difference in the complexing ability of different rare earths and the carrier (such as the difference in distribution coefficient) is utilized to achieve the selective migration of the target rare earth. The selective migration of the target rare earth can achieve efficient separation of rare earths and impurities. For example, the emulsion film is dispersed in the rare earth liquid (membrane outer phase), and the rare earth ions (RE³⁺) and the mobile carrier (such as P204) form a complex on the outer surface of the membrane and diffuse through the liquid film to the internal phase interface. P204 has a higher affinity for neodymium Nd³⁺ than aluminum, which can achieve efficient separation of rare earths and impurities. 3. Stripping and enrichment: At the interface of the inner phase of the emulsion membrane, the rare earth complex reacts with the acidic solution, and the rare earth elements are desorbed into the inner phase aqueous solution, while the carrier returns to the outer phase of the membrane for reuse. This process forms a rare earth enriched solution with an inner phase rare earth concentration of more than 50 g / L. Fourth, demulsification and phase separation, using high-voltage electrostatic method or centrifugal method to destroy the emulsion membrane structure and separate the organic phase and rare earth-rich internal phase solution; the organic phase loss rate after demulsification must be controlled below 1% to reduce costs, and the organic phase is recycled into the organic phase recovery tank 3; 5. Purify rare earths by passing the rare earth-rich solution in step 4 into the rare earth-rich inner phase solution barrel 4, and then subjecting the rare earth-rich solution to precipitation, filtration, and calcination to obtain high-purity rare earth oxides with a purity of ≥99.9%; The main body of the device for extracting and separating rare earths in this embodiment includes: A high-shear emulsification device 1, an extraction kettle 2 connected to the high-shear emulsification device 1, an organic phase recovery barrel 3 connected to the extraction kettle 2, and a rare earth-rich internal phase solution barrel 4 connected to the extraction kettle 2. The extraction kettle 2 is connected to a bubbling oil film extraction device, and the extraction kettle 2 is connected to an ultrasonic generator. When in use, emulsification entrainment will be generated when the rare earth liquid and the extractant are mixed, affecting the mixing effect. The mixing is not considered complete until the emulsification entrainment completely disappears. During the mixing process, the ultrasonic generator emits ultrasonic waves to the mixture, accelerating separation and reducing emulsification entrainment, thereby accelerating the mixing rate of the rare earth liquid and the extractant.
[0024] Furthermore, after the emulsion membrane is prepared in step 1, a porous support can be prepared. The porous support can be made of, for example, polysulfone or polyacrylonitrile. When used, the porous support is immersed in the emulsion membrane, and the membrane fills the pores through capillary action to ensure the stability of the emulsion membrane. When the porous support is used, a surfactant such as hydroxypropyl cellulose can be added to reduce the interfacial tension of the emulsion membrane and enhance the binding stability between the membrane and the support. Furthermore, it also includes a bubbling oil film extraction device, which is connected to the extraction kettle 2 and can accelerate the oil film extraction process in the extraction kettle 2. The bubbling oil film extraction device is divided into a bubble generation and dispersion device and an oil-in-gas dispersed phase reactor; the bubble generation and dispersion device uses the bubbling technology of inert gas to disperse the organic extractant into bubbles covered by a thin layer of oil film, thereby increasing the mass transfer area; the oil-in-gas dispersed phase reactor uses the oil-in-gas microstructure design and combines the reverse flow of the water phase to enhance the selective migration of rare earth ions, and is suitable for the enrichment of extremely low concentration REO <100 mg / L solution.
[0025] Combine Figure 1-Figure 2 , a device and method for extracting and separating rare earths in this embodiment, the specific use process is as follows: first, prepare a liquid membrane, mix the matrix, mobile carrier and surfactant in proportion, and form a stable emulsion liquid membrane through a high shear emulsification device 1, then mix the rare earth raw material and the acidic solution into a rare earth feed liquid, and then inject the emulsion liquid membrane and the rare earth feed liquid into the extraction kettle 2, the rare earth ions and the mobile carrier form a complex on the outer surface of the membrane, and diffuse through the liquid membrane to the inner phase interface of the acidic desorbent in the inner phase of step 1; utilize the difference in the complexing ability of different rare earths and carriers to achieve the selective migration of the target rare earth; the rare earth complex reacts with the acidic solution, the rare earth elements are desorbed into the inner phase aqueous solution, and the carrier returns to the outer phase of the membrane for reuse; the rare earth concentration in the inner phase formed by this process can reach 50 g / L or more rare earth-enriched liquid; finally, a high-voltage electrostatic method or a centrifugal method is used to destroy the emulsion membrane structure and separate the organic phase and the rare earth-rich inner phase solution; the organic phase loss rate after demulsification needs to be controlled below 1% to reduce costs, and the organic phase is recycled and circulated into the organic phase recovery barrel 3, so that high-purity rare earth elements can be extracted without pollution.
[0026] Although the present invention has been described above with reference to specific embodiments, various modifications may be made thereto and components may be replaced with equivalents without departing from the scope of the present invention. In particular, as long as no structural conflicts exist, the various features of the embodiments disclosed herein may be combined with one another in any manner, and the omission of an exhaustive description of such combinations in this specification is solely for the sake of space and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.
Claims
1. A method for extracting and separating rare earth, characterized in that: include: Liquid membrane preparation: sulfonated kerosene matrix, mobile carrier P204 and surfactant acid blue 113 are mixed in proportion and passed through a high shear emulsification device to form a stable emulsion liquid membrane with an oil-in-water structure and an acidic desorbent as the internal phase; rare earth raw materials and acidic solution are mixed to form a rare earth liquid; Extraction reaction: first pour the rare earth liquid into the extraction kettle, then disperse the emulsion film formed in the high shear emulsification equipment in the rare earth liquid, and the rare earth ions and the mobile carrier form a complex on the outer surface of the membrane and diffuse through the liquid membrane to the internal phase interface; Utilize the differences in the complexing ability between different rare earths and carriers to achieve the selective migration of target rare earths; Back extraction and enrichment: at the interface of the inner phase of the emulsion membrane, the rare earth complex reacts with the acidic solution, the rare earth elements are desorbed into the inner phase aqueous solution, and the carrier returns to the outer phase of the membrane for reuse; Demulsification and phase separation: high-voltage electrostatic method or centrifugal method is used to destroy the emulsion membrane structure and separate the organic phase and rare earth-rich inner phase solution; after demulsification, the organic phase is recycled and circulated into the organic phase recovery tank; Purifying rare earth, passing the rare earth-rich solution into the rare earth-rich inner phase solution barrel, and then precipitating, filtering and burning the rare earth-rich solution.
2. The method for extracting and separating rare earths according to claim 1, characterized in that: After the emulsion liquid membrane is prepared, a porous support is made. The porous support is made of polysulfone or polyacrylonitrile. When in use, the porous support is immersed in the emulsion liquid membrane, and the liquid membrane fills the pores through capillary action to ensure the stability of the emulsion liquid membrane.
3. The method for extracting and separating rare earth according to claim 2, characterized in that: When the porous support is in use, surfactant hydroxypropyl cellulose is added to reduce the interfacial tension of the emulsion liquid film and enhance the bonding stability between the liquid film and the support.
4. A device for extracting and separating rare earth, characterized in that: include: A high shear emulsification device (1), an extraction kettle (2) connected to the high shear emulsification device (1), an organic phase recovery barrel (3) connected to the extraction kettle (2), and a rare earth-rich internal phase solution barrel (4) connected to the extraction kettle (2), the extraction kettle (2) being connected to a bubbling oil film extraction device, and the extraction kettle (2) being connected to an ultrasonic generator.
5. The device for extracting and separating rare earth according to claim 4, characterized in that: The bubbling oil film extraction equipment accelerates the oil film extraction process in the extraction kettle (2), and the bubbling oil film extraction equipment is divided into a bubble generation and dispersion device and an oil-in-gas dispersed phase reactor.
6. The device for extracting and separating rare earth according to claim 5, characterized in that: The bubble generation and dispersion device utilizes inert gas bubbling technology to disperse the organic extractant into bubbles coated with a thin oil film, thereby increasing the mass transfer area. The gas-in-oil dispersed phase reactor utilizes a gas-in-oil microstructure design combined with reverse flow of the aqueous phase to enhance the selective migration of rare earth ions, making it suitable for enriching solutions with concentrations less than 100 mg / L.
Citation Information
Cited By
Intelligent regulation and control method for rare earth extraction process
CN120821254A