Device and method for extracting and separating rare earth

Abstract

The invention relates to a device and a method for extracting and separating rare earth, the device comprises an extraction tower body, the top end of the extraction tower body is communicated with an organic phase clarification section, and the bottom end of the extraction tower body is communicated with a water phase clarification section; the inner diameter of the organic phase clarification section and the inner diameter of the water phase clarification section are both larger than the inner diameter of the extraction tower body; the side wall of the water phase clarifying section is connected with a pulse device; an inner component is arranged in an inner cavity of the extraction tower body and comprises a combination of a baffle plate and a sieve plate. The device filled with the novel internal component is used for extracting and separating rare earth, the separation effect is excellent, operation is easy, environment friendliness is achieved, and the device has good application prospects in the field of rare earth separation.

Description

Technical Field

[0001] The invention relates to the technical field of rare earth extraction and separation, and in particular to a device and method for extracting and separating rare earth. Background Art

[0002] Solvent extraction is one of the main industrial methods for rare earth separation and purification. In the actual industrial process, the difference in the distribution coefficients of different rare earth ions between the extractant and the aqueous phase is used to separate and purify rare earth elements through extraction, washing, and stripping. The traditional extraction device is a mixing and settling tank, but the mixing and settling tank has the problems of large tank pressure, poor sealing, and a large number of extraction equipment. The investment cost and equipment operation and maintenance cost are high, and the amount of organic matter volatilization is large.

[0003] The extraction tower is a continuous countercurrent extraction equipment. During the extraction process, the water and oil phases can be continuously extracted without separation. A single device has multiple theoretical stages, which effectively reduces the amount of extraction agent pressure tank and the number of extraction equipment. As a commonly used means of energy introduction, pulses can enhance the movement of liquid in the extraction tower by alternating ventilation and exhaust, thereby improving the liquid-liquid two-phase mixing and mass transfer performance. For example, CN109182792A discloses a pulse sieve plate tower for rare earth extraction, comprising a tower body, a base, multiple groups of sieve plates, a driving motor, a transmission shaft, multiple groups of left rotating rods, multiple groups of right rotating rods, multiple groups of left connecting columns, multiple groups of right connecting columns, multiple groups of left limit plates, multiple groups of right limit plates, multiple groups of left first springs, multiple groups of left second springs, multiple groups of left vibration plates, multiple groups of right first springs, multiple groups of right second springs, multiple groups of right vibration plates, a left pull ring, a right pull ring, a left pull rope, a right pull rope, a left front fixing ring, a left rear fixing ring, a right front fixing ring, a right rear fixing ring, a left rotating shaft, a right rotating shaft, a left supporting plate, a right supporting 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. The washing liquid and the rare earth extracting liquid can be fully contacted with each other in countercurrent on multiple groups of sieve plates, thereby improving the rare earth separation effect.

[0004] CN104294063A discloses a method for extracting and recovering rare earths from a low-concentration rare earth solution, which uses a rare earth solution containing medium and heavy rare earths as a raw material solution, and includes the following steps: using a first organic phase containing an acidic phosphorus extractant with a PKa value>4 to extract the raw material solution for the first time, to obtain a primary loaded organic phase and a primary raffinate; extracting the primary raffinate for the second time with a second organic phase containing an acidic phosphorus extractant with a PKa value<3.5, to obtain a secondary loaded organic phase and a secondary raffinate; respectively stripping and recovering the rare earths in the primary loaded organic phase and the secondary loaded organic phase, to obtain a high-concentration rare earth chloride solution. The 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, in view of the shortcomings of the prior art, it is necessary to provide a device method for achieving efficient separation and purification of rare earths under relatively small pulse energy input. Summary of the invention

[0006] The purpose of the present invention is to provide a device and method for extracting and separating rare earths. The device loaded with new internal components is used to extract and separate rare earths. The device has excellent separation effect, simple operation, and is environmentally friendly. It has good application prospects in the field of rare earth separation.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a device for extracting and separating rare earths, the device comprising an extraction tower body, the top end of the extraction tower body being connected to an organic phase clarification section, and the bottom end being connected to a water phase clarification section; the inner diameters of the organic phase clarification section and the water phase clarification section are both larger than the inner diameter of the extraction tower body; the side wall of the water phase clarification section is connected to a pulse device; the inner cavity of the extraction tower body is provided with an internal component, the internal component comprising a combination of a baffle and a sieve plate.

[0009] The device for extracting and separating rare earths provided by the present invention selects a combination of a baffle and a sieve plate as a new internal component of an extraction tower body for a rare earth extraction system, which can realize the alternating breakup and aggregation of droplets in the extraction tower body, improve the mass transfer efficiency, greatly improve the theoretical number of stages per unit height of the device, and at the same time reduce the amount of tank pressure, reduce the amount of organic volatilization, reduce cost investment, and achieve 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 body, for example, 1.5 times, 1.8 times, 2 times, 2.2 times or 2.5 times, but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

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

[0012] Preferably, the side wall of the organic phase clarification section is provided with a water phase inlet and an organic phase outlet.

[0013] Preferably, the side wall of the water phase clarification section is provided with an organic phase inlet and a water phase outlet.

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

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

[0016] Preferably, the pulse device comprises 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 water phase clarification section.

[0017] The pressure reducing valve of the present invention is a commercially available pressure reducing valve that meets the working conditions; the three-way valve is a commercially available three-way valve that meets the working conditions.

[0018] Preferably, the three-way valve comprises an electric control valve or a pneumatic control valve, and when the power is off or the air is cut off, the respective side connecting end is connected to the straight outlet end, and when the power is on or the air is ventilated, the respective inlet end is connected to the side connecting end.

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

[0020] Preferably, the diameter of the pulse leg is 1 / 5-1 / 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, and other unlisted values ​​within the numerical range are also applicable.

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

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

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

[0024] Preferably, the baffles include hydrophilic baffles and / or hydrophobic baffles.

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

[0026] Preferably, the contact angle between the surface of the material used for the hydrophilic baffle and the hydrophilic sieve plate and water is <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 numerical range are also applicable, preferably <50°.

[0027] Preferably, the contact angle between the surface of the material used for the hydrophobic baffle and the hydrophobic sieve plate and water is >90°, for example, it can be 95°, 100°, 105°, 110° or 115°, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably >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 stripping section extraction device, and the structures of the washing section extraction device and the stripping section extraction device are the same as the structure of the device for extracting and separating rare earths.

[0029] In the present invention, the extraction section extraction device, the washing section extraction device and the stripping section extraction device are connected in series as the extraction section, the washing section and the stripping section. The extraction section extraction device, the washing section extraction device and the stripping section extraction device can all be used separately to complete the rare earth extraction section, the washing section and the stripping 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 stripping section extraction device.

[0031] In a second aspect, the present invention provides a method for extracting and separating rare earths, the method being carried out by the device for extracting and separating rare earths according to the first aspect, the method comprising the following steps:

[0032] The organic phase containing the blank extractant contacts with the water phase containing the rare earth elements for extraction, the obtained raffinate is discharged from the water phase clarification section, and the obtained organic phase loaded with rare earths is discharged from the organic phase clarification section; in the extraction, the extraction system in the device is pulse treated after the interface between the water and oil phases is stabilized.

[0033] The method for extracting and separating rare earths provided by the present invention is aimed at a rare earth extraction system, can realize efficient separation and purification of rare earths under the condition of relatively small pulse energy input, matches the corresponding extraction process, and can avoid flooding of the extraction tower while significantly improving the rare earth extraction effect, thereby ensuring the normal operation of the extraction equipment. The method is simple to operate, environmentally friendly, highly safe, can greatly reduce production safety risks, and has good application prospects in the field of rare earth separation.

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

[0035] Preferably, taking the total volume fraction of P507 and diluent as 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 numerical range are also applicable, preferably 40-60%, and the remainder is diluent.

[0036] Preferably, the diluent comprises sulphonated kerosene.

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

[0038] Preferably, the rare earth elements in the aqueous phase containing rare earth elements include any one of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium or yttrium, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of lanthanum and cerium, a combination of praseodymium, neodymium, promethium and samarium, and a 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 the rare earth element 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 numerical range are also applicable, preferably (2-4):1.

[0040] Preferably, after the rare earth-loaded organic phase is discharged, it is contacted with an aqueous phase that does not contain rare earth elements or contains medium and heavy rare earths for washing, and the resulting raffinate is discharged from the aqueous phase clarification section, and the resulting medium and heavy rare earth-loaded organic phase is discharged from the organic phase clarification section; during the washing, the extraction system in the device is pulse-treated after the water-oil two-phase interface is stabilized.

[0041] Preferably, the acidity of the aqueous phase containing no rare earth elements or containing medium and heavy rare earths 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 values ​​not listed within the numerical range are also applicable, preferably 0.1-0.5 mol / L.

[0042] Preferably, the medium-heavy rare earths in the medium-heavy rare earth-containing aqueous phase include any one of samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium or yttrium, or a combination of at least two of them. Typical but non-limiting combinations include a combination of samarium and europium, a combination of gadolinium, terbium, dysprosium and holmium, or a 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 earths 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 numerical range are also applicable, preferably 1:1.

[0044] Preferably, after the organic phase loaded with heavy rare earths is discharged, it is contacted with an aqueous phase free of rare earth elements for stripping, the resulting rare earth-containing raffinate is discharged from the aqueous phase clarification section, and the resulting blank organic phase is discharged from the organic phase clarification section; during the stripping, the extraction system in the device is pulse-treated after the water-oil two-phase interface is stabilized.

[0045] Preferably, the acidity of the aqueous phase free of 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 numerical range are also applicable, preferably 5-6 mol / L.

[0046] Preferably, the volume flow ratio of the organic phase loaded with heavy rare earths to the aqueous phase containing no 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 numerical range are also applicable, preferably 1:1.

[0047] Preferably, the step of controlling the stability of the water-oil two-phase interface includes: when a water-oil two-phase interface appears during the extraction, washing or stripping 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 treatment includes compressed air or compressed inert gas.

[0049] Preferably, the pulse amplitude of the pulse treatment is 2-4 cm of 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 is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] Preferably, the pulse frequency of the pulse treatment is 1-10s for each reciprocating distance, for example, 1s, 3s, 5s, 8s or 10s, but is not limited to the listed values, and other values ​​not listed within the numerical 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 earths provided by the present invention selects a combination of a baffle plate and a sieve plate as a new internal component of the extraction tower body for the rare earth extraction system, which can realize the alternate breakup and aggregation of droplets in the extraction tower body, improve the mass transfer efficiency, greatly increase the theoretical number of stages per unit height of the device, and at the same time reduce the amount of tank pressure, reduce the amount of organic volatilization, reduce the cost investment, 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 conditions, match the corresponding extraction process, and 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, highly safe, and can significantly reduce production safety risks. It has good application prospects in the field of rare earth separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a schematic diagram of the structure of the device for extracting and separating rare earth provided in Example 1 of the present invention;

[0055] Figure 2 It is a schematic diagram of the connection between the device for extracting and separating rare earth provided in Example 1 of the present invention and the washing section extraction device and the stripping section extraction device;

[0056] Wherein: 1, extraction tower body; 2, organic phase clarification section; 3, water phase clarification section; 4, water phase inlet; 5, organic phase outlet; 6, organic phase inlet; 7, water phase outlet; 8, flow control device; 9, pulse leg; 10, pressure reducing valve; 11, three-way valve; 12, hydrophilic baffle; 13, hydrophobic sieve plate. DETAILED DESCRIPTION

[0057] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0058] Example 1

[0059] This embodiment provides a device for extracting and separating rare earths, the structural schematic diagram of which is shown in FIG. Figure 1 As shown, the device comprises an extraction tower body 1, the extraction tower body 1 has a height of 1m and an inner diameter of 20cm, the top of the extraction tower body 1 is connected to an organic phase clarification section 2, and the bottom is connected to a water phase clarification section 3; the inner diameters of the organic phase clarification section 2 and the water phase clarification section 3 are both twice the inner diameter of the extraction tower body 1; the heights of the organic phase clarification section 2 and the water phase clarification section 3 are both 0.5m; the side wall of the organic phase clarification section 2 is provided with a water phase inlet 4 and an organic phase outlet 5; the side wall of the water phase clarification section 2 is provided with an organic phase inlet 6 and a water phase outlet 7; the water phase inlet 4, the organic phase inlet 6 and the water phase outlet 7 are provided with a flow control device 8;

[0060] The side wall of the water phase clarification section 3 is connected with a pulse device, which includes a pulse leg 9, on which a pressure reducing valve 10 and a three-way valve 11 are arranged, 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 water 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 0.5m higher than the organic phase outlet 5;

[0061] The inner cavity of the extraction tower body 1 is provided with hydrophilic baffles 12 and hydrophobic sieve plates 13 arranged alternately, and the ratio of the hydrophobic sieve plates 13 to the hydrophilic baffles 12 is 1:3; the contact angle between the surface of the material used for the hydrophobic sieve plates 13 and water is 115°, and the contact angle between the surface of the material used for the hydrophilic baffles 12 and water is 40°;

[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 stripping section extraction device. The structures of the washing section extraction device and the stripping section extraction device are the same as those of the device for extracting and separating rare earth. The connection diagram is shown in FIG. Figure 2 As shown; a transfer tank is 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 stripping section extraction device.

[0063] Example 2

[0064] This embodiment provides a device for extracting and separating rare earths. 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 0.8 m; 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 50.8 m higher than the organic phase outlet; the surface contact angle of the material used for the hydrophobic sieve plate 13 and water is 110°, and the surface contact angle of the material used for the hydrophilic baffle 12 and water is 50°, and the rest are the same as Embodiment 1.

[0065] Example 3

[0066] This embodiment provides a device for extracting and separating rare earths. 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 1 m; 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 1 m higher than the organic phase outlet; the surface contact angle of the material used for the hydrophobic sieve plate 13 and water is 95°, and the surface contact angle of the material used for the hydrophilic baffle 12 and water is 60°, and the rest is the same as Embodiment 1.

[0067] Example 4

[0068] This embodiment provides a device for extracting and separating rare earths. The difference from Embodiment 1 is that, except for adjusting the ratio of the hydrophobic sieve plate 13 to the hydrophilic baffle plate 12 to 1:4, the rest is the same as Embodiment 1.

[0069] Example 5

[0070] This embodiment provides a device for extracting and separating rare earths. The difference from Embodiment 1 is that, except for adjusting the ratio of the hydrophobic sieve plate 13 to the hydrophilic baffle plate 12 to 1:2, the rest is the same as Embodiment 1.

[0071] Example 6

[0072] This embodiment provides a device for extracting and separating rare earths. The difference from Embodiment 1 is that the hydrophilic baffle 12 is replaced by a hydrophobic baffle. The contact angle between the surface of the material used for the hydrophobic baffle and water is 115°. The rest is the same as Embodiment 1.

[0073] Comparative Example 1

[0074] This comparative example provides a device for extracting and separating rare earths. The difference from Example 1 is that no hydrophobic sieve plate 13 is provided, and the rest is the same as Example 1.

[0075] Comparative Example 2

[0076] This comparative example provides a device for extracting and separating rare earths. The difference from Example 1 is that no hydrophilic baffle 12 is provided, and the rest is the same as Example 1.

[0077] Application Example 1

[0078] This application example provides a method for extracting and separating rare earths, which is performed by the device provided in Example 1 and comprises the following steps:

[0079] The organic phase containing the blank extractant and the water phase containing the rare earth elements are contacted with each other at a volume flow ratio of 3:1 for extraction, and the obtained raffinate is discharged from the water phase clarification section 3, and the obtained 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 interface between the water and oil phases is stabilized;

[0080] The organic phase containing the blank extractant is a mixed solution obtained by mixing P507 and sulfonated kerosene and saponifying with a sodium hydroxide solution; taking the total volume fraction of P507 and sulfonated kerosene as 100%, the P507 is 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] The organic phase loaded with rare earths having a volume flow ratio of 1:1 is discharged and then contacted with an aqueous phase containing no rare earth elements or containing medium and heavy rare earths for washing, and the obtained raffinate is discharged from the aqueous phase clarification section of the washing section extraction device, and the obtained organic phase loaded with medium and heavy rare earths is discharged from the organic phase clarification section of the washing section extraction device; during the washing, after the water-oil two-phase interface is stabilized, the extraction system in the device is subjected to pulse treatment; the acidity of the aqueous phase containing no rare earth elements or containing medium and heavy rare earths is 0.3 mol / L; the medium and heavy rare earths in the aqueous phase containing medium and heavy rare earths include samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and yttrium;

[0082] The organic phase loaded with medium and heavy rare earths with a volume flow ratio of 1:1 is discharged and then contacted with a water phase without rare earth elements for stripping, and the obtained rare earth-containing raffinate is discharged from the water phase clarification section of the stripping section extraction device, and the obtained blank organic phase is discharged from the organic phase clarification section of the stripping section extraction device; during the stripping, the extraction system in the device is subjected to pulse treatment after the water-oil two-phase interface is stabilized; the acidity of the water phase without rare earth elements is 5 mol / L;

[0083] The control step of stabilizing the water-oil two-phase interface comprises: when the water-oil two-phase interface appears during the extraction, washing or stripping and is higher than the water phase outlet 7 of the device, adjusting the flow rate of the water phase outlet 7 of the device to be equal to the flow rate of the water phase inlet 4 of the device;

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

[0085] Application Example 2

[0086] This application example provides a method for extracting and separating rare earths, which differs from Application Example 1 in that the volume flow ratio of the organic phase containing a blank extractant to the aqueous phase containing rare earth elements is adjusted to 1:1; the volume fraction of the P507 is adjusted to 20%; the volume flow ratio of the organic phase loaded with rare earths to the aqueous phase not containing rare earth elements or containing medium-heavy rare earths is adjusted to 0.5:1, and the acidity of the aqueous phase not containing rare earth elements or containing medium-heavy rare earths is adjusted to 0.01 mol / L; the volume flow ratio of the organic phase loaded with medium-heavy rare earths to the aqueous phase not containing rare earth elements is adjusted to 0.5:1, and the acidity of the aqueous phase not containing rare earth elements is adjusted to 4 mol / L; the pulse amplitude of the pulse treatment is adjusted to a reciprocating distance of 2 cm for the fluid in the device, and the pulse frequency is adjusted to a time required for each reciprocating distance of 1 s, and the rest is the same as Application Example 1.

[0087] Application Example 3

[0088] This application example provides a method for extracting and separating rare earths, which differs from Application Example 1 in that the volume flow ratio of the organic phase containing a blank extractant to the aqueous phase containing rare earth elements is adjusted to 5:1; the volume fraction of the P507 is adjusted to 70%; the volume flow ratio of the organic phase loaded with rare earths to the aqueous phase not containing rare earth elements or containing medium-heavy rare earths is adjusted to 2:1, and the acidity of the aqueous phase not containing rare earth elements or containing medium-heavy rare earths is adjusted to 2 mol / L; the volume flow ratio of the organic phase loaded with medium-heavy rare earths to the aqueous phase not containing rare earth elements is adjusted to 2:1, and the acidity of the aqueous phase not containing rare earth elements is adjusted to 4-7 mol / L; the pulse amplitude of the pulse treatment is adjusted to a reciprocating distance of 4 cm for the fluid in the device, and the pulse frequency is adjusted to a time required for each reciprocating distance of 10 s, and the rest is the same as Application Example 1.

[0089] Application Example 4

[0090] This application example provides a method for extracting and separating rare earths. The difference from Application Example 1 is that, except for adjusting the pulse amplitude of the pulse treatment to a reciprocating distance of 1.5 cm for the fluid in the device, the rest is the same as Application Example 1.

[0091] Application Example 5

[0092] This application example provides a method for extracting and separating rare earths. The difference from Application Example 1 is that, except for adjusting the pulse amplitude of the pulse treatment to a reciprocating distance of 4.5 cm for the fluid in the device, the rest is the same as Application Example 1.

[0093] Application Example 6

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

[0095] Application Example 7

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

[0097] Application Example 8

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

[0099] Application Example 9

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

[0101] Application Example 10

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

[0103] Comparative application example 1

[0104] This comparative application example provides a method for extracting and separating rare earths. The method is carried out using the device provided in comparative example 1, and the steps of the method are the same as those of application example 1.

[0105] Comparative Application Example 2

[0106] This comparative application example provides a method for extracting and separating rare earths. The method is carried out using the device provided in comparative example 2, and the steps of the method are the same as those of application example 1.

[0107] The rare earth is extracted and separated by the method provided in Application Examples 1-10 and Comparative Application Examples 1 and 2, and the rare earth single-stage extraction rate is calculated. The formula is: F Re =C Re出 ×W 出 / C Re入 ×W 入 ; Among them, F Re is the single-stage extraction rate of rare earth, C Re出 is the rare earth concentration in the outlet water phase, C Re入 is the rare earth concentration in the inlet water phase, W 出 , W 入 are the flow rates of the outlet water phase and the inlet water phase respectively, and the results are shown in Table 1; a liquid level meter is used to detect whether liquid flooding occurs in the device, and the results are shown in Table 1.

[0108] Table 1

[0109] Rare earth single-stage extraction rate / % Is it flooding? 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] From Table 1 we can know that:

[0111] By comparing Application Example 1 with Application Examples 4 and 5, it can be seen that in the method for extracting and separating rare earth provided by the present invention, the pulse has a significant effect on the rare earth extraction rate. A pulse amplitude that is too low will reduce the rare earth extraction rate, and a pulse amplitude that is too high will cause liquid flooding in the extraction tower body. Among them, the pulse amplitude extraction effect of Application Example 1 is the best;

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

[0113] From the comparison between Application Example 1 and Application Example 10, it can be seen that the combination of the hydrophobic sieve plate and the hydrophilic baffle plate can significantly improve the rare earth extraction rate;

[0114] From the comparison between Application Example 1 and Comparative Application Examples 1 and 2, it can be seen that the present invention uses a device loaded with new internal components to extract and separate rare earths, which can significantly improve the rare earth extraction effect while avoiding liquid flooding in the extraction tower body, thereby ensuring the normal operation of the extraction equipment.

[0115] In summary, the device for extracting and separating rare earths provided by the present invention selects a combination of a baffle plate and a sieve plate as a new internal component of the extraction tower body for the rare earth extraction system, which can realize the alternate breakup and aggregation of droplets in the extraction tower body, improve the mass transfer efficiency, greatly improve the theoretical number of stages per unit height of the device, and at the same time reduce the amount of tank pressure, reduce the amount of organic volatilization, reduce the cost investment, and achieve the effect of protecting the environment;

[0116] The method for extracting and separating rare earths provided by the present invention can realize efficient separation and purification of rare earths under the condition of relatively small pulse energy input, match the corresponding extraction process, significantly improve the rare earth extraction effect, avoid flooding of the extraction tower, and ensure the normal operation of the extraction equipment. The method is simple to operate, environmentally friendly, highly safe, can greatly reduce production safety risks, and has good application prospects in the field of rare earth separation.

[0117] The above description is only a specific implementation mode 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 thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A device for extracting and separating rare earth, characterized in that: The device comprises an extraction tower body, the top end of which is connected to an organic phase clarification section, and the bottom end of which is connected to a water phase clarification section; the inner diameters of the organic phase clarification section and the water phase clarification section are both larger than the inner diameter of the extraction tower body; a pulse device is connected to the side wall of the water phase clarification section; an inner cavity of the extraction tower body is provided with an internal component, and the internal component comprises a combination of a baffle and a sieve plate.

2. The device according to claim 1, characterized in that 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 body; Preferably, the heights of the organic phase clarification section and the water phase clarification section are both ≥ 0.5 m; Preferably, the side wall of the organic phase clarification section is provided with a water phase inlet and an organic phase outlet; Preferably, the side wall of the water phase clarification section is provided with an organic phase inlet and a water phase outlet; Preferably, flow control devices are provided at the water phase inlet, the organic phase inlet and the water phase outlet.

3. The device according to claim 2, characterized in that The pulse device comprises a pulse leg, on which a pressure reducing valve and a three-way valve are arranged, 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 water phase clarification section; Preferably, the height of the outlet of the pulse leg is lower than the height of the organic phase inlet; Preferably, the diameter of the pulse leg is 1 / 5-1 / 3 of the diameter of the extraction tower body; Preferably, the inlet of the pulse leg is located 0.5-1 m higher than the organic phase outlet.

4. The device according to any one of claims 1 to 3, characterized in that: The baffles and the sieve plates are arranged alternately; Preferably, the ratio of the sieve plate to the baffle is 1:3; Preferably, the baffles include hydrophilic baffles and / or hydrophobic baffles; Preferably, the sieve plate comprises a hydrophilic sieve plate and / or a hydrophobic sieve plate; Preferably, the contact angle between the surface of the material used for the hydrophilic baffle and the hydrophilic sieve plate and water is less than 90°, preferably less than 50°; Preferably, the contact angle between the surface of the material used for the hydrophobic baffle and the hydrophobic sieve plate and water is both greater than 90°, preferably greater than 110°.

5. The device according to claim 2 or 3, 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 stripping section extraction device. The structures of the washing section extraction device and the stripping section extraction device are the same as the structure of the device for extracting and separating rare earths; 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 stripping section extraction device.

6. A method for extracting and separating rare earth, characterized in that: The method is carried out by the device for extracting and separating rare earths according to any one of claims 1 to 5, and the method comprises the following steps: The organic phase containing the blank extractant contacts with the water phase containing the rare earth elements for extraction, the obtained raffinate is discharged from the water phase clarification section, and the obtained organic phase loaded with rare earths is discharged from the organic phase clarification section; in the extraction, the extraction system in the device is pulse treated after the interface between the water and oil phases is stabilized.

7. The method according to claim 6, characterized in that The organic phase containing the blank extractant is a mixed solution obtained by mixing P507 with a diluent and saponifying with an alkali solution; Preferably, based on the total volume fraction of P507 and the diluent being 100%, the P507 is 20-70%, preferably 40-60%, and the remainder is the diluent; Preferably, the diluent comprises sulphonated kerosene; Preferably, the alkali solution comprises any one of sodium hydroxide solution, ammonia water or calcium hydroxide solution or a combination of at least two thereof; Preferably, the rare earth element in the aqueous phase containing rare earth elements includes any one of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium or yttrium, or a combination of at least two thereof; Preferably, the volume flow ratio of the organic phase containing the blank extractant to the aqueous phase containing the rare earth element is (1-5):1, preferably (2-4):

1.

8. The method according to claim 6 or 7, characterized in that: After the rare earth-loaded organic phase is discharged, it is contacted with an aqueous phase that does not contain rare earth elements or contains medium and heavy rare earths for washing, and the obtained raffinate is discharged from the aqueous phase clarification section, and the obtained medium and heavy rare earth-loaded organic phase is discharged from the organic phase clarification section; during the washing, after the water-oil two-phase interface is stabilized, the extraction system in the device is pulse treated; Preferably, the acidity of the aqueous phase containing no rare earth elements or containing medium and heavy rare earths is 0.01-2 mol / L, preferably 0.1-0.5 mol / L; Preferably, the medium-heavy rare earth in the medium-heavy rare earth-containing aqueous phase includes any one or a combination of at least two of samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium or yttrium; 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 earths is (0.5-2):1, preferably 1:

1.

9. The method according to claim 8, characterized in that After the organic phase loaded with medium and heavy rare earths is discharged, it is contacted with a water phase without rare earth elements for stripping, and the obtained rare earth-containing raffinate is discharged from the water phase clarification section, and the obtained blank organic phase is discharged from the organic phase clarification section; during the stripping, the extraction system in the device is pulse-treated after the interface between the water and oil phases is stabilized; Preferably, the acidity of the aqueous phase not containing rare earth elements is 4-7 mol / L, preferably 5-6 mol / L; Preferably, the volume flow ratio of the organic phase loaded with medium and heavy rare earths to the aqueous phase free of rare earth elements is (0.5-2):1, preferably 1:

1.

10. The method according to claim 9, characterized in that The step of controlling the stability of the water-oil two-phase interface comprises: when the water-oil two-phase interface appears during the extraction, washing or stripping 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; Preferably, the compressed gas introduced in the pulse treatment includes compressed air or compressed inert gas; Preferably, the pulse amplitude of the pulse treatment is 2-4 cm of the reciprocating distance of the fluid in the device; Preferably, the pulse frequency of the pulse treatment is 1-10s, preferably 1-5s, for each reciprocating distance.

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