Apparatus and method for extracting and separating rare earths

Abstract

The application relates to a device and a method for extracting and separating rare earths, wherein the device comprises an extraction tower body, the top end of the extraction tower body is connected with an organic phase clarification section, the bottom end is connected with an aqueous phase clarification section, the inner diameters of the organic phase clarification section and the aqueous phase clarification section are larger than the inner diameter of the extraction tower body, the side wall of the aqueous phase clarification section is connected with a pulse device, and the inner cavity of the extraction tower body is provided with an inner member, the inner member comprises a combination of baffle plates and sieve plates. The device filled with the novel inner member is used for extracting and separating rare earths, the separation effect is excellent, the operation is simple, the device is environment-friendly, and the device has a good application prospect in the field of rare earth separation.

Description

Technical Field

[0001] This invention relates to the field of rare earth extraction and separation technology, specifically to an apparatus and method for extracting and separating rare earth elements. Background Technology

[0002] Solvent extraction is one of the main industrial methods for the separation and purification of rare earth elements. In actual industrial processes, the differences in the partition coefficients of different rare earth ions between the extractant and the aqueous phase are utilized to achieve the separation and purification of rare earth elements through extraction, washing, and back-extraction stages. Traditional extraction devices are mixing and clarification tanks, but these tanks suffer from problems such as large tank volume, poor sealing, and a large number of extraction devices, resulting in high investment and equipment maintenance costs, as well as a large amount of volatile organic compounds.

[0003] An extraction tower is a continuous countercurrent extraction device that allows for continuous extraction of water and oil phases without separation. A single device can have multiple theoretical stages, effectively reducing the amount of extractant required and the number of extraction devices needed. Pulsing, as a commonly used energy introduction method, can enhance the liquid movement within the extraction tower through alternating ventilation and exhaust, thereby improving the mixing and mass transfer performance of the liquid-liquid two-phase mixture. For example, CN109182792A discloses a pulse sieve plate tower for rare earth extraction, which includes a tower body, a base, multiple sets of sieve plates, a drive motor, a transmission shaft, multiple sets of left rotating rods, multiple sets of right rotating rods, multiple sets of left connecting columns, multiple sets of right connecting columns, multiple sets of left limiting plates, multiple sets of right limiting plates, multiple sets of left first springs, multiple sets of left second springs, multiple sets of left vibrating plates, multiple sets of right first springs, multiple sets of right second springs, multiple sets of right vibrating plates, a left pull ring, a right pull ring, a left pull rope, a right pull rope, a left front fixed ring, a left rear fixed ring, a right front fixed ring, a right rear fixed ring, a left rotating shaft, a right rotating shaft, a left support plate, a right support plate, a left adjusting plate, a right adjusting plate, a left locking seat, a right locking seat, a left fixing bolt, and a right fixing bolt. It allows the washing liquid and rare earth extract to come into full countercurrent contact on multiple sets of sieve plates, thereby improving the rare earth separation effect.

[0004] CN104294063A discloses a method for extracting and recovering rare earth elements from a low-concentration rare earth solution. The method uses a rare earth solution containing medium-heavy rare earth elements as the raw material and includes the following steps: A first organic phase containing an acidic phosphorus extractant with a pKa value > 4 is used for a first extraction of the raw material, yielding a primary loaded organic phase and a primary raffinate; the primary raffinate is then used for a second extraction with a second organic phase containing an acidic phosphorus extractant with a pKa value < 3.5, yielding a secondary loaded organic phase and a secondary raffinate; rare earth elements are then back-extracted from both the primary and secondary loaded organic phases to obtain a high-concentration rare earth chloride solution. This invention can achieve efficient and clean extraction of low-concentration rare earth solutions. However, for the rare earth-P507 system, relying solely on pulse-enhanced two-phase mass transfer requires a strong pulse energy input, resulting in a high compressed air load and high energy consumption.

[0005] Therefore, to address the shortcomings of existing technologies, there is a need to provide a device and method for achieving efficient separation and purification of rare earth elements with relatively small pulse energy input. Summary of the Invention

[0006] The purpose of this invention is to provide an apparatus and method for extracting and separating rare earth elements. The apparatus, which uses novel internal components, extracts and separates rare earth elements, achieving excellent separation results. It is also simple to operate, environmentally friendly, and has good application prospects in the field of rare earth separation.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an apparatus for extracting and separating rare earth elements. The apparatus includes an extraction tower body, the top of which is connected to an organic phase clarification section and the bottom of which is connected to an aqueous phase clarification section. The inner diameters of both the organic phase clarification section and the aqueous phase clarification section are larger than the inner diameter of the extraction tower body. A pulse device is connected to the side wall of the aqueous phase clarification section. The inner cavity of the extraction tower body is provided with internal components, the internal components including a combination of baffles and sieves.

[0009] The device for extracting and separating rare earth elements provided by this invention selects a combination of baffles and sieves as a novel internal component of the extraction tower for rare earth extraction systems. This allows for alternating droplet breakage and coalescence within the extraction tower, improving mass transfer efficiency and significantly increasing the theoretical number of stages per unit height of the device. At the same time, it reduces the amount of pressure tank, lowers the amount of organic matter volatilization, reduces costs, and achieves the effect of protecting the environment.

[0010] Preferably, the inner diameters of the organic phase clarification section and the aqueous phase clarification section are both 1.5-2.5 times the inner diameter of the extraction tower, for example, 1.5 times, 1.8 times, 2 times, 2.2 times or 2.5 times, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0011] Preferably, the height of both the organic phase clarification section and the aqueous phase clarification section is ≥0.5m, for example, it can be 0.5m, 0.6m, 0.8m, 0.9m or 1m, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] Preferably, the sidewall of the organic phase clarification section is provided with an aqueous phase inlet and an organic phase outlet.

[0013] Preferably, the sidewall of the aqueous clarification section is provided with an organic phase inlet and an aqueous phase outlet.

[0014] Preferably, flow control devices are provided at the aqueous phase inlet, organic phase inlet, and aqueous phase outlet.

[0015] The flow control device includes a flow meter and a flow regulation device.

[0016] Preferably, the pulse device includes a pulse leg, on which a pressure reducing valve and a three-way valve are provided. The inlet of the pulse leg is used to introduce compressed gas, and the outlet of the pulse leg is connected to the side wall of the aqueous clarification section.

[0017] The pressure reducing valve described in this invention is a commercially available pressure reducing valve that meets the operating conditions; the three-way valve is a commercially available three-way valve that meets the operating conditions.

[0018] Preferably, the three-way valve includes an electrically controlled valve or a pneumatically controlled valve, which connects its respective side connection end to the straight outlet end in the event of power failure or gas failure, and connects its respective inlet end to the side connection end in the event of power failure or gas supply.

[0019] Preferably, the height of the pulse leg outlet is lower than the height of the organic phase inlet.

[0020] Preferably, the diameter of the pulse leg is 1 / 5 to 1 / 3 of the diameter of the extraction tower body, for example, it can be 1 / 5, 1 / 4 or 1 / 3, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the inlet of the pulse leg is located 0.5-1m higher than the outlet of the organic phase, for example, it can be 0.5m, 0.6m, 0.8m, 0.9m or 1m, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, the baffles and sieves are arranged alternately.

[0023] Preferably, the ratio of the sieve plate to the baffle plate is 1:3.

[0024] Preferably, the baffle includes a hydrophilic baffle and / or a hydrophobic baffle.

[0025] Preferably, the sieve plate includes a hydrophilic sieve plate and / or a hydrophobic sieve plate.

[0026] Preferably, the surface of the material used for the hydrophilic baffle and the hydrophilic sieve plate has a contact angle with water of less than 90°. For example, it can be 80°, 70°, 60°, 50° or 40°, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably less than 50°.

[0027] Preferably, the surface of the material used for the hydrophobic baffle and the hydrophobic sieve plate has a contact angle with water that is greater than 90°. For example, it can be 95°, 100°, 105°, 110° or 115°, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably greater than 110°.

[0028] Preferably, the organic phase outlet is connected to a washing section extraction device, and the organic phase outlet of the washing section extraction device is connected to a back-extraction section extraction device. The structures of the washing section extraction device and the back-extraction section extraction device are the same as those of the device for extracting and separating rare earth elements.

[0029] In this invention, the extraction section extraction device, the washing section extraction device, and the back-extraction section extraction device are connected in series as the extraction section, washing section, and back-extraction section. The extraction section extraction device, the washing section extraction device, and the back-extraction section extraction device can all be used independently to complete the rare earth extraction section, washing section, and back-extraction section process.

[0030] Preferably, a transfer tank is provided between the organic phase outlet and the washing section extraction device, and between the organic phase outlet of the washing section extraction device and the back-extraction section extraction device.

[0031] Secondly, the present invention provides a method for extracting and separating rare earth elements, the method being carried out using the apparatus for extracting and separating rare earth elements described in the first aspect, the method comprising the following steps:

[0032] The organic phase containing blank extractant is contacted with the aqueous phase containing rare earth elements for extraction. The resulting raffinate is discharged from the aqueous phase clarification section, and the resulting rare earth-loaded organic phase is discharged from the organic phase clarification section. During the extraction, the extraction system in the device is pulse-treated after the water-oil interface stabilizes.

[0033] The method for extracting and separating rare earth elements provided by this invention is designed for rare earth extraction systems. It can achieve efficient separation and purification of rare earth elements with relatively small pulse energy input. When matched with a corresponding extraction process, it can significantly improve the rare earth extraction effect while avoiding flooding in the extraction tower and ensuring the normal operation of the extraction equipment. The method is simple to operate, environmentally friendly, and highly safe, and can greatly reduce production safety risks. It has good application prospects in the field of rare earth separation.

[0034] Preferably, the organic phase containing the blank extractant is a mixture obtained by mixing P507 with a diluent and then saponifying it with an alkali solution.

[0035] Preferably, with the total volume fraction of P507 and diluent being 100%, the P507 is 20-70%, for example, it can be 20%, 30%, 40%, 50%, 60% or 70%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 40-60%, with the remainder being diluent.

[0036] Preferably, the diluent comprises sulfonated kerosene.

[0037] Preferably, the alkaline solution includes any one or a combination of at least two of sodium hydroxide solution, ammonia solution, or calcium hydroxide solution. Typical but non-limiting combinations include a combination of sodium hydroxide solution and ammonia solution, a combination of ammonia solution and calcium hydroxide solution, or a combination of sodium hydroxide solution, ammonia solution, and calcium hydroxide solution.

[0038] Preferably, the rare earth elements in the aqueous phase containing rare earth elements include any one or a combination of at least two of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, or yttrium. Typical but non-limiting combinations include the combination of lanthanum and cerium, the combination of praseodymium, neodymium, promethium, and samarium, and the combination of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium.

[0039] Preferably, the volume flow ratio of the organic phase containing the blank extractant to the aqueous phase containing rare earth elements is (1-5):1, for example, it can be 1:1, 2:1, 3:1, 4:1 or 5:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably (2-4):1.

[0040] Preferably, after the rare earth-loaded organic phase is discharged, it is washed by contacting an aqueous phase that does not contain rare earth elements or contains medium and heavy rare earth elements. The resulting raffinate is discharged from the aqueous phase clarification section, and the resulting organic phase loaded with medium and heavy rare earth elements is discharged from the organic phase clarification section. During the washing process, after the water-oil two-phase interface stabilizes, the extraction system in the device is subjected to pulse treatment.

[0041] Preferably, the acidity of the aqueous phase containing no rare earth elements or containing medium and heavy rare earth elements is 0.01-2 mol / L, for example, it can be 0.01 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 1 mol / L or 2 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.1-0.5 mol / L.

[0042] Preferably, the medium-heavy rare earth elements in the aqueous phase containing medium-heavy rare earth elements include any one or a combination of at least two of samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, or yttrium. Typical but non-limiting combinations include the combination of samarium and europium, the combination of gadolinium, terbium, dysprosium, and holmium, or the combination of samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium.

[0043] Preferably, the volume flow ratio of the rare earth-loaded organic phase to the aqueous phase containing no rare earth elements or containing medium and heavy rare earth elements is (0.5-2):1, for example, it can be 0.5:1, 1:1, 1.2:1, 1.5:1 or 2:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1:1.

[0044] Preferably, after the organic phase containing heavy rare earth elements in the load is discharged, it is back-extracted by contacting the aqueous phase that does not contain rare earth elements. The resulting raffinate containing rare earth elements is discharged from the aqueous phase clarification section, and the resulting blank organic phase is discharged from the organic phase clarification section. During the back-extraction, the extraction system in the device is pulse-treated after the interface between the water and oil phases has stabilized.

[0045] Preferably, the acidity of the aqueous phase without rare earth elements is 4-7 mol / L, for example, it can be 4 mol / L, 5 mol / L, 5.5 mol / L, 6 mol / L or 7 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 5-6 mol / L.

[0046] Preferably, the volumetric flow rate ratio of the organic phase containing heavy rare earth elements to the aqueous phase without rare earth elements in the load is (0.5-2):1, for example, it can be 0.5:1, 1:1, 1.2:1, 1.5:1 or 2:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1:1.

[0047] Preferably, the control step for stabilizing the water-oil two-phase interface includes: when the water-oil two-phase interface appears during extraction, washing or back-extraction and is higher than the water phase outlet of the device, adjusting the water phase outlet flow rate of the device to be equal to the water phase inlet flow rate of the device.

[0048] Preferably, the compressed gas introduced in the pulse processing includes compressed air or compressed inert gas.

[0049] Preferably, the pulse amplitude of the pulse processing is 2-4 cm, which is the reciprocating distance of the fluid in the device. For example, it can be 2 cm, 2.5 cm, 3 cm, 3.5 cm or 4 cm, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0050] Preferably, the pulse frequency of the pulse processing is 1-10s for the time required for each reciprocating distance, for example, it can be 1s, 3s, 5s, 8s or 10s, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1-5s.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] (1) The device for extracting and separating rare earth provided by the present invention selects a combination of baffles and sieves as a new type of internal component of the extraction tower for the rare earth extraction system. This can realize the alternating breaking and coalescence of droplets in the extraction tower, improve the mass transfer efficiency, greatly increase the theoretical number of stages per unit height of the device, reduce the amount of pressure tank, reduce the amount of organic matter volatilization, reduce the cost input, and achieve the effect of protecting the environment.

[0053] (2) The method for extracting and separating rare earths provided by the present invention can achieve efficient separation and purification of rare earths under relatively small pulse energy input. When matched with the corresponding extraction process, it can significantly improve the rare earth extraction effect while avoiding flooding of the extraction tower and ensuring the normal operation of the extraction equipment. The method is simple to operate, environmentally friendly, and highly safe, and can greatly reduce production safety risks. It has good application prospects in the field of rare earth separation. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the rare earth extraction and separation apparatus provided in Embodiment 1 of the present invention;

[0055] Figure 2 This is a schematic diagram showing the connection between the rare earth extraction and separation device, the washing section extraction device, and the back-extraction section extraction device provided in Embodiment 1 of the present invention.

[0056] The components are: 1. Extraction tower body; 2. Organic phase clarification section; 3. Aqueous phase clarification section; 4. Aqueous phase inlet; 5. Organic phase outlet; 6. Organic phase inlet; 7. Aqueous phase outlet; 8. Flow control device; 9. Pulse leg; 10. Pressure reducing valve; 11. Three-way valve; 12. Hydrophilic baffle plate; 13. Hydrophobic sieve plate. Detailed Implementation

[0057] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0058] Example 1

[0059] This embodiment provides an apparatus for extracting and separating rare earth elements, as shown in the schematic diagram below. Figure 1 As shown, the device includes an extraction tower 1 with a height of 1m and an inner diameter of 20cm. The top of the extraction tower 1 is connected to an organic phase clarification section 2, and the bottom is connected to an aqueous phase clarification section 3. The inner diameters of both the organic phase clarification section 2 and the aqueous phase clarification section 3 are twice the inner diameter of the extraction tower 1. The heights of both the organic phase clarification section 2 and the aqueous phase clarification section 3 are 0.5m. An aqueous phase inlet 4 and an organic phase outlet 5 are provided on the side wall of the organic phase clarification section 2. An organic phase inlet 6 and an aqueous phase outlet 7 are provided on the side wall of the aqueous phase clarification section 2. Flow control devices 8 are provided at the aqueous phase inlet 4, the organic phase inlet 6, and the aqueous phase outlet 7.

[0060] A pulse device is connected to the side wall of the aqueous phase clarification section 3. The pulse device includes a pulse leg 9, on which a pressure reducing valve 10 and a three-way valve 11 are installed. The inlet of the pulse leg 9 is used to introduce compressed gas, and the outlet of the pulse leg 9 is connected to the side wall of the aqueous phase clarification section 3. The height of the outlet of the pulse leg 9 is lower than the height of the organic phase inlet 6. The diameter of the pulse leg 9 is 1 / 4 of the diameter of the extraction tower body 1. The position of the inlet of the pulse leg 9 is higher than the organic phase outlet 5 by 0.5m.

[0061] The inner cavity of the extraction tower body 1 is provided with alternating hydrophilic baffles 12 and hydrophobic sieves 13, the ratio of hydrophobic sieves 13 to hydrophilic baffles 12 is 1:3; the surface of the material used for the hydrophobic sieves 13 has a contact angle of 115° with water, and the surface of the material used for the hydrophilic baffles 12 has a contact angle of 40° with water.

[0062] The organic phase outlet 5 is connected to a washing section extraction device, and the organic phase outlet of the washing section extraction device is connected to a back-extraction section extraction device. The structures of the washing section extraction device and the back-extraction section extraction device are the same as those of the device for extracting and separating rare earth elements. A schematic diagram of the connection is shown below. Figure 2 As shown, transfer tanks are provided between the organic phase outlet 5 and the washing section extraction device, and between the organic phase outlet of the washing section extraction device and the back-extraction section extraction device.

[0063] Example 2

[0064] This embodiment provides an apparatus for extracting and separating rare earth elements. The difference from Embodiment 1 is that the inner diameters of the organic phase clarification section 2 and the aqueous phase clarification section 3 are both adjusted to 1.5 times the inner diameter of the extraction tower body 1, and the heights of the organic phase clarification section 2 and the aqueous phase clarification section 3 are both adjusted to 0.8m; the diameter of the pulse leg 9 is adjusted to 1 / 3 of the diameter of the extraction tower body 1; the position of the inlet of the pulse leg 9 is adjusted to be 50.8m higher than the organic phase outlet; the surface of the hydrophobic sieve plate 13 has a water contact angle of 110°, and the surface of the hydrophilic baffle plate 12 has a water contact angle of 50°. The rest are the same as in Embodiment 1.

[0065] Example 3

[0066] This embodiment provides an apparatus for extracting and separating rare earth elements. The difference from Embodiment 1 is that the inner diameters of the organic phase clarification section 2 and the aqueous phase clarification section 3 are both adjusted to 2.5 times the inner diameter of the extraction tower body 1, and the heights of the organic phase clarification section 2 and the aqueous phase clarification section 3 are both adjusted to 1m; the diameter of the pulse leg 9 is adjusted to 1 / 5 of the diameter of the extraction tower body 1; the position of the inlet of the pulse leg 9 is adjusted to be 5.1m higher than the organic phase outlet; the surface of the hydrophobic sieve plate 13 has a water contact angle of 95°, and the surface of the hydrophilic baffle plate 12 has a water contact angle of 60°. The rest are the same as in Embodiment 1.

[0067] Example 4

[0068] This embodiment provides an apparatus for extracting and separating rare earth elements. The difference between this embodiment and Embodiment 1 is that, except for adjusting the ratio of the hydrophobic sieve plate 13 to the hydrophilic baffle plate 12 to 1:4, everything else is the same as in Embodiment 1.

[0069] Example 5

[0070] This embodiment provides an apparatus for extracting and separating rare earth elements. The difference between this embodiment and Embodiment 1 is that, except for adjusting the ratio of the hydrophobic sieve plate 13 to the hydrophilic baffle plate 12 to 1:2, everything else is the same as in Embodiment 1.

[0071] Example 6

[0072] This embodiment provides an apparatus for extracting and separating rare earth elements. The difference from Embodiment 1 is that the hydrophilic baffle 12 is replaced with a hydrophobic baffle. The surface of the material used in the hydrophobic baffle has a contact angle of 115° with water. All other aspects are the same as in Embodiment 1.

[0073] Comparative Example 1

[0074] This comparative example provides an apparatus for extracting and separating rare earth elements. The difference from Example 1 is that the hydrophobic sieve plate 13 is not provided, but all other aspects are the same as in Example 1.

[0075] Comparative Example 2

[0076] This comparative example provides an apparatus for extracting and separating rare earth elements. The difference between this apparatus and Example 1 is that the hydrophilic baffle 12 is not provided; otherwise, they are the same as in Example 1.

[0077] Application Example 1

[0078] This application example provides a method for extracting and separating rare earth elements. The method is performed using the apparatus provided in Example 1 and includes the following steps:

[0079] An organic phase containing blank extractant with a volume flow ratio of 3:1 is contacted with an aqueous phase containing rare earth elements for extraction. The resulting raffinate is discharged from the aqueous phase clarification section 3, and the resulting rare earth-loaded organic phase is discharged from the organic phase clarification section 2. During the extraction, the extraction system in the device is pulse-treated after the water-oil two-phase interface stabilizes.

[0080] The organic phase containing the blank extractant is a mixture obtained by mixing P507 and sulfonated kerosene and saponifying it with sodium hydroxide solution; with the total volume fraction of P507 and sulfonated kerosene being 100%, P507 accounts for 50%, and the remainder is sulfonated kerosene; the rare earth elements in the aqueous phase containing rare earth elements include lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium;

[0081] After the organic phase loaded with rare earth elements at a volume flow ratio of 1:1 is discharged, it is washed by contacting an aqueous phase that does not contain rare earth elements or contains medium and heavy rare earth elements. The resulting raffinate is discharged from the aqueous phase clarification section of the washing section extraction device, and the resulting organic phase loaded with medium and heavy rare earth elements is discharged from the organic phase clarification section of the washing section extraction device. During the washing process, after the interface between the water and oil phases stabilizes, the extraction system in the device is subjected to pulse treatment. The acidity of the aqueous phase that does not contain rare earth elements or contains medium and heavy rare earth elements is 0.3 mol / L. The medium and heavy rare earth elements in the aqueous phase containing medium and heavy rare earth elements include samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium.

[0082] After the organic phase containing heavy rare earth elements in the load is discharged at a volume flow ratio of 1:1, it is contacted with an aqueous phase free of rare earth elements for back-extraction. The resulting raffinate containing rare earth elements is discharged from the aqueous phase clarification section of the back-extraction extraction device, and the resulting blank organic phase is discharged from the organic phase clarification section of the back-extraction extraction device. During the back-extraction, the extraction system in the device is pulse-treated after the water-oil interface stabilizes. The acidity of the aqueous phase free of rare earth elements is 5 mol / L.

[0083] The control steps for stabilizing the water-oil two-phase interface include: when the water-oil two-phase interface appears during extraction, washing or back-extraction and is higher than the water phase outlet 7 of the device, the flow rate of the water phase outlet 7 of the device is adjusted to be equal to the flow rate of the water phase inlet 4 of the device.

[0084] The compressed gas introduced in the pulse processing is compressed air; the pulse amplitude of the pulse processing is 3 cm for the fluid reciprocating distance in the device, and the pulse frequency is 3 s for the time required for each reciprocating distance.

[0085] Application Example 2

[0086] This application example provides a method for extracting and separating rare earth elements. The difference from Application Example 1 is that the volume flow ratio of the organic phase containing the blank extractant to the aqueous phase containing rare earth elements is adjusted to 1:1; the volume fraction of P507 is adjusted to 20%; the volume flow ratio of the organic phase loaded with rare earth elements to the aqueous phase without rare earth elements or containing medium-heavy rare earth elements is adjusted to 0.5:1, and the acidity of the aqueous phase without rare earth elements or containing medium-heavy rare earth elements is adjusted to 0.01 mol / L; the volume flow ratio of the organic phase loaded with medium-heavy rare earth elements to the aqueous phase without rare earth elements is adjusted to 0.5:1, and the acidity of the aqueous phase without rare earth elements is adjusted to 4 mol / L; the pulse amplitude of the pulse treatment is adjusted to a fluid reciprocating distance of 2 cm within the device, and the pulse frequency is adjusted to the time required for each reciprocating distance of 1 s. All other aspects are the same as in Application Example 1.

[0087] Application Example 3

[0088] This application example provides a method for extracting and separating rare earth elements. The difference from Application Example 1 is that the volume flow ratio of the organic phase containing the blank extractant to the aqueous phase containing rare earth elements is adjusted to 5:1; the volume fraction of P507 is adjusted to 70%; the volume flow ratio of the organic phase loaded with rare earth elements to the aqueous phase without rare earth elements or containing medium-heavy rare earth elements is adjusted to 2:1, and the acidity of the aqueous phase without rare earth elements or containing medium-heavy rare earth elements is adjusted to 2 mol / L; the volume flow ratio of the organic phase loaded with medium-heavy rare earth elements to the aqueous phase without rare earth elements is adjusted to 2:1, and the acidity of the aqueous phase without rare earth elements is adjusted to 4-7 mol / L; the pulse amplitude of the pulse treatment is adjusted to a fluid reciprocating distance of 4 cm within the device, and the pulse frequency is adjusted to the time required for each reciprocating distance of 10 s. All other aspects are the same as in Application Example 1.

[0089] Application Example 4

[0090] This application example provides a method for extracting and separating rare earth elements. The difference between this method and Application Example 1 is that, except for adjusting the pulse amplitude of the pulse treatment to a reciprocating distance of 1.5 cm within the device, all other aspects are the same as in Application Example 1.

[0091] Application Example 5

[0092] This application example provides a method for extracting and separating rare earth elements. The difference between this method and Application Example 1 is that, except for adjusting the pulse amplitude of the pulse treatment to a reciprocating distance of 4.5 cm within the device, all other aspects are the same as in Application Example 1.

[0093] Application Example 6

[0094] This application example provides a method for extracting and separating rare earth elements. The method is carried out using the apparatus provided in Example 2, and the steps of the method are the same as those in Application Example 1.

[0095] Application Example 7

[0096] This application example provides a method for extracting and separating rare earth elements. The method is carried out using the apparatus provided in Example 3, and the steps of the method are the same as those in Application Example 1.

[0097] Application Example 8

[0098] This application example provides a method for extracting and separating rare earth elements. The method is carried out using the apparatus provided in Example 4, and the steps of the method are the same as those in Application Example 1.

[0099] Application Example 9

[0100] This application example provides a method for extracting and separating rare earth elements. The method is carried out using the apparatus provided in Example 5, and the steps of the method are the same as those in Application Example 1.

[0101] Application Example 10

[0102] This application example provides a method for extracting and separating rare earth elements. The method is carried out using the apparatus provided in Example 6, and the steps of the method are the same as those in Application Example 1.

[0103] Comparative Application Example 1

[0104] This comparative application example provides a method for extracting and separating rare earth elements, which is carried out using the apparatus provided in Comparative Example 1, and the steps of the method are the same as those in Application Example 1.

[0105] Comparative Application Example 2

[0106] This comparative application example provides a method for extracting and separating rare earth elements, which is carried out using the apparatus provided in Comparative Example 2, and the steps of the method are the same as those in Application Example 1.

[0107] Rare earth elements were extracted and separated using the methods provided in Application Examples 1-10 and Comparative Application Examples 1 and 2. The single-stage extraction rate of rare earth elements was calculated using the formula: F Re =C Re出 ×W 出 / C Re入 ×W 入 Among them, F Re For rare earth single-stage extraction rate, C Re出 C represents the rare earth concentration in the outlet aqueous phase. Re入 W represents the rare earth element concentration in the inlet aqueous phase. 出 W 入 The flow rates of the outlet and inlet water phases are shown in Table 1. The results are also shown in Table 1, which detects whether flooding has occurred in the liquid level gauge.

[0108] Table 1

[0109] Application Example 1 25.1 no Application Example 2 20.3 no Application Example 3 / yes Application Example 4 20.6 no Application Example 5 / yes Application Example 6 23.2 no Application Example 7 17.2 no Application Example 8 16.2 no Application Example 9 / yes Application Example 10 16.8 no Comparative Application Example 1 10.2 no Comparative Application Example 2 / yes

[0110] Table 1 shows that:

[0111] As can be seen from the comparison between Application Example 1 and Application Examples 4 and 5, in the method for extracting and separating rare earths provided by the present invention, the pulse has a significant impact on the rare earth extraction rate. If the pulse amplitude is too low, the rare earth extraction rate will be reduced, and if the pulse amplitude is too high, the liquid in the extraction tower will flood. Among them, the pulse amplitude of Application Example 1 has the best extraction effect.

[0112] A comparison of Application Example 1 with Application Examples 8 and 9 shows that the ratio of sieve plate to baffle plate has a significant impact on the rare earth extraction rate. Too low a ratio of sieve plate will reduce the rare earth extraction rate, while too high a ratio of sieve plate will cause flooding in the extraction tower. Among them, the extraction effect is best when the ratio of sieve plate to baffle plate in Application Example 1 is 1:3.

[0113] A comparison of Application Example 1 and Application Example 10 shows that the combination of hydrophobic sieve plate and hydrophilic baffle plate can significantly improve the rare earth extraction rate.

[0114] As can be seen from the comparison between Application Example 1 and Comparative Application Examples 1 and 2, the device of the present invention, which uses a novel internal component to extract and separate rare earth elements, can significantly improve the rare earth extraction effect while avoiding flooding in the extraction tower and ensuring the normal operation of the extraction equipment.

[0115] In summary, the rare earth extraction and separation device provided by this invention selects a combination of baffles and sieves as a novel internal component of the extraction tower for the rare earth extraction system. This enables the alternating breaking and coalescence of droplets within the extraction tower, improving mass transfer efficiency and greatly increasing the theoretical number of stages per unit height of the device. At the same time, it reduces the amount of pressure tank, reduces the amount of organic matter volatilization, reduces cost input, and achieves the effect of protecting the environment.

[0116] The method for extracting and separating rare earth elements provided by this invention can achieve efficient separation and purification of rare earth elements with relatively small pulse energy input. When matched with a corresponding extraction process, it can significantly improve the rare earth extraction effect while avoiding flooding in the extraction tower and ensuring the normal operation of the extraction equipment. The method is simple to operate, environmentally friendly, and highly safe, and can greatly reduce production safety risks. It has good application prospects in the field of rare earth separation.

[0117] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An apparatus for extracting and separating rare earth elements, characterized in that, The device includes an extraction tower body, the top of which is connected to an organic phase clarification section and the bottom of which is connected to an aqueous phase clarification section; the inner diameters of both the organic phase clarification section and the aqueous phase clarification section are larger than the inner diameter of the extraction tower body; a pulse device is connected to the side wall of the aqueous phase clarification section; the inner cavity of the extraction tower body is provided with internal components, the internal components including a combination of baffles and sieves; the baffles and sieves are arranged alternately; the ratio of sieves to baffles is 1:3; the baffles are hydrophilic baffles; the sieves are hydrophobic sieves.

2. The apparatus according to claim 1, characterized in that, The inner diameters of both the organic phase clarification section and the aqueous phase clarification section are 1.5-2.5 times the inner diameter of the extraction tower.

3. The apparatus according to claim 1, characterized in that, The height of both the organic phase clarification section and the aqueous phase clarification section is ≥0.5m.

4. The apparatus according to claim 1, characterized in that, The sidewall of the organic phase clarification section is provided with an aqueous phase inlet and an organic phase outlet.

5. The apparatus according to claim 4, characterized in that, The sidewall of the aqueous clarification section is provided with an organic phase inlet and an aqueous phase outlet.

6. The apparatus according to claim 5, characterized in that, Flow control devices are installed at the aqueous phase inlet, organic phase inlet, and aqueous phase outlet.

7. The apparatus according to claim 5, characterized in that, The pulse device includes a pulse leg, which is equipped with a pressure reducing valve and a three-way valve. The inlet of the pulse leg is used to introduce compressed gas, and the outlet of the pulse leg is connected to the side wall of the aqueous clarification section.

8. The apparatus according to claim 7, characterized in that, The height of the pulse leg's outlet is lower than the height of the organic phase inlet.

9. The apparatus according to claim 7, characterized in that, The diameter of the pulse leg is 1 / 5 to 1 / 3 of the diameter of the extraction tower.

10. The apparatus according to claim 7, characterized in that, The inlet of the pulse leg is located 0.5-1m higher than the outlet of the organic phase.

11. The apparatus according to claim 1, characterized in that, The surface of the material used in the hydrophilic baffle has a contact angle with water of <90°.

12. The apparatus according to claim 11, characterized in that, The surface of the material used in the hydrophilic baffle has a contact angle with water of <50°.

13. The apparatus according to claim 1, characterized in that, The contact angle between the surface of the material used in the hydrophobic sieve plate and water is >90°.

14. The apparatus according to claim 13, characterized in that, The contact angle between the surface of the material used in the hydrophobic sieve plate and water is >110°.

15. The apparatus according to claim 4, characterized in that, The organic phase outlet is connected to a washing section extraction device, and the organic phase outlet of the washing section extraction device is connected to a back-extraction section extraction device. The structures of the washing section extraction device and the back-extraction section extraction device are the same as those of the device for extracting and separating rare earth elements.

16. The apparatus according to claim 15, characterized in that, A transfer tank is provided between the organic phase outlet and the washing section extraction device, and between the organic phase outlet of the washing section extraction device and the back-extraction section extraction device.

17. A method for extracting and separating rare earth elements, characterized in that, The method is carried out using the apparatus for rare earth extraction and separation according to any one of claims 1-16, and the method includes the following steps: The organic phase containing blank extractant is contacted with the aqueous phase containing rare earth elements for extraction. The resulting raffinate is discharged from the aqueous phase clarification section, and the resulting rare earth-loaded organic phase is discharged from the organic phase clarification section. During the extraction, the extraction system in the device is pulse-treated after the water-oil interface stabilizes.

18. The method according to claim 17, characterized in that, The organic phase containing the blank extractant is a mixture obtained by mixing P507 with a diluent and then saponifying it with an alkaline solution.

19. The method according to claim 18, characterized in that, With the total volume fraction of P507 and diluent being 100%, P507 accounts for 20-70%, and the remainder is diluent.

20. The method according to claim 19, characterized in that, With the total volume fraction of P507 and diluent being 100%, P507 accounts for 40-60%, and the remainder is diluent.

21. The method according to claim 18, characterized in that, The diluent includes sulfonated kerosene.

22. The method according to claim 18, characterized in that, The alkaline solution includes any one or a combination of at least two of sodium hydroxide solution, ammonia solution, or calcium hydroxide solution.

23. The method according to claim 17, characterized in that, The rare earth elements in the aqueous phase containing rare earth elements include any one or a combination of at least two of the following: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, or yttrium.

24. The method according to claim 17, characterized in that, The volume flow rate ratio of the organic phase containing the blank extractant to the aqueous phase containing rare earth elements is (1-5):

1.

25. The method according to claim 24, characterized in that, The volume flow rate ratio of the organic phase containing the blank extractant to the aqueous phase containing rare earth elements is (2-4):

1.

26. The method according to claim 17, characterized in that, After the rare earth-loaded organic phase is discharged, it is washed by contacting an aqueous phase that does not contain rare earth elements or contains medium and heavy rare earth elements. The resulting raffinate is discharged from the aqueous phase clarification section, and the resulting organic phase loaded with medium and heavy rare earth elements is discharged from the organic phase clarification section. During the washing process, after the water-oil two-phase interface stabilizes, the extraction system in the device is subjected to pulse treatment.

27. The method according to claim 26, characterized in that, The acidity of the aqueous phase, which contains no rare earth elements or contains medium and heavy rare earth elements, is 0.01-2 mol / L.

28. The method according to claim 27, characterized in that, The acidity of the aqueous phase, which contains no rare earth elements or contains medium and heavy rare earth elements, is 0.1-0.5 mol / L.

29. The method according to claim 26, characterized in that, The medium and heavy rare earth elements in the aqueous phase containing medium and heavy rare earth elements include any one or a combination of at least two of samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, or yttrium.

30. The method according to claim 26, characterized in that, The volumetric flow rate ratio of the rare earth-loaded organic phase to the aqueous phase containing no rare earth elements or containing medium and heavy rare earth elements is (0.5-2):

1.

31. The method according to claim 30, characterized in that, The volume flow ratio of the rare earth-loaded organic phase to the aqueous phase containing no rare earth elements or containing medium and heavy rare earth elements is 1:

1.

32. The method according to claim 26, characterized in that, After the organic phase containing heavy rare earth elements in the load is discharged, it is back-extracted by contacting the aqueous phase that does not contain rare earth elements. The resulting raffinate containing rare earth elements is discharged from the aqueous phase clarification section, and the resulting blank organic phase is discharged from the organic phase clarification section. During the back-extraction, the extraction system in the device is pulse-treated after the water-oil two-phase interface stabilizes.

33. The method according to claim 32, characterized in that, The acidity of the aqueous phase, which does not contain rare earth elements, is 4-7 mol / L.

34. The method according to claim 33, characterized in that, The acidity of the aqueous phase, which does not contain rare earth elements, is 5-6 mol / L.

35. The method according to claim 32, characterized in that, The volumetric flow rate ratio of the organic phase containing heavy rare earth elements to the aqueous phase without rare earth elements in the load is (0.5-2):

1.

36. The method according to claim 35, characterized in that, The volume flow rate ratio of the organic phase containing heavy rare earth elements to the aqueous phase without rare earth elements in the load is 1:

1.

37. The method according to claim 32, characterized in that, The control steps for stabilizing the water-oil two-phase interface include: when the water-oil two-phase interface appears during extraction, washing or back-extraction and is higher than the water phase outlet of the device, the water phase outlet flow rate of the device is adjusted to be equal to the water phase inlet flow rate of the device.

38. The method according to claim 17, characterized in that, The compressed gas introduced in the pulse processing includes compressed air or compressed inert gas.

39. The method according to claim 17, characterized in that, The pulse amplitude of the pulse processing is 2-4 cm, which is the reciprocating distance of the fluid inside the device.

40. The method according to claim 17, characterized in that, The pulse frequency of the pulse processing is 1-10 seconds, which is the time required for each reciprocating distance.

41. The method according to claim 40, characterized in that, The pulse frequency of the pulse processing is 1-5 seconds, which is the time required for each reciprocating distance.

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