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    • 专利摘要:
    A liquid-liquid extraction unit includes an 5 extraction/separation tank (10) into which an aqueous phase in bubble form is admitted from an upper inlet (20) in one sidewall and an organic phase in bubble form is admitted from a lower inlet (30) in the one sidewall. The upward moving organic phase is contacted with the downward moving aqueous 10 phase. After contact, the organic phase is discharged through an upper outlet (40) in an opposite sidewall and the aqueous phase is discharged through a lower outlet (50) in the opposite sidewall. -12
    公开号:AU2013200062A1
    申请号:U2013200062
    申请日:2013-01-07
    公开日:2013-08-01
    发明作者:Takehisa Minowa；Hiroto Sugahara
    申请人:Shin Etsu Chemical Co Ltd；
    IPC主号:B01D11-04
    专利说明:
    10 15 TECHNICAL FIELD This invention relates to a liquid-liquid extraction unit adapted to contact an aqueous phase with an organic phase, separate them, and recover the desired extract from the thus separated aqueous phase and/or organic phase, more 20 particularly, to a liquid-liquid extraction unit suitable for the extraction and separation of rare earth elements, especially rare earth elements including yttrium and light rare earth elements (La, Ce, Pr, Nd, Sm, and Eu); a multistage liquid-liquid extraction apparatus and a 25 multistage continuous extraction system using the unit. BACKGROUND ART Nowadays, rare earth magnets as typified by Nd magnets are widely used in motors, sensors and other parts built in 30 hard disk drives, air conditioners, hybrid cars, and the like. Typical rare earth elements used in rare earth magnets include cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), terbium (Tb) and dysprosium (Dy). For the separation of these rare earth elements, the ion exchange 35 resin (or solid-liquid extraction) method and the solvent extraction (or liquid-liquid extraction) method are known. The solvent extraction method is often used In the industrial -1aseparation and purification of rare earth elements because the method is capable of efficient large-scale treatment due to continuous steps. In the solvent extraction method, a water phase consisting of an aqueous solution containing 5 metal elements to be separated is contacted with an organic phase consisting of an extractant for extracting a metal element of interest and an organic solvent for diluting the extractant. Then the metal element of interest is extracted with the extractant into the organic phase for separation. 10 Extraction apparatus known in the art for use in extracting rare earth elements by the solvent extraction (or liquid-liquid extraction) method include a multistage continuous extraction system comprising a plurality of mixer-settlers as shown in FIG. 5 (see Patent Documents 1, 2 15 and 3). Illustrated in FIG. 5 are an extraction section A for extracting a selected rare earth element from an aqueous phase into an organic phase, a scrubber section B for scrubbing the organic phase, and a back extraction section C for back extracting the rare earth element once extracted in 20 the organic phase into an aqueous phase for recovery. Arrows 1 to 9 indicate lines and flows of aqueous phase, organic phase, and reagents into and out of the mixer-settlers. A rare earth element-containing aqueous phase from line 1, an extractant-containing organic phase from line 2, 25 and an alkaline aqueous solution from line 3 are fed into the mixer-settler of extraction section A, where the steps of mixing aqueous and organic phases, stationary holding and separating them again are repeated in multiple stages, whereby the rare earth element of interest is extracted from, 30 the aqueous phase into the organic phase, which is fed to scrubber section B. The aqueous phase is discharged via line 5, and the rare earth element which remains in the aqueous phase without being extracted into the organic phase is recovered from this aqueous phase. The alkaline aqueous 35 solution from line 3 is fed for adjusting the equilibrium acid concentration. -2- In scrubber section B, an acid aqueous solution is fed from line 4 as the aqueous phase into the mixer-settler, where the steps of mixing the acid aqueous solution (aqueous phase) 4 with the organic phase having the rare earth element 5 extracted therein in extraction section A, stationary holding and separating them again are repeated in multiple stages. The organic phase 2 is scrubbed or washed in that only the rare earth element, which is contained in the organic phase 2 and should essentially remain in the aqueous phase in 10 extraction section A, is selectively extracted into the acid aqueous solution (aqueous phase) 4, after which the organic phase 2 is delivered to back-extraction section C. On the other hand, the acid aqueous solution (aqueous phase) having only the rare earth element, which should essentially remain 15 in the aqueous phase in extraction section A, selectively extracted therein Is discharged via line 9, and fed back to extraction section A. Notably, the acid aqueous solution 4 is adjusted to such an acid concentration that only the rare earth element, which is dissolved in a minor amount in the 20 organic phase 2 and should remain in the aqueous phase, may be selectively extracted. In back extraction section C, the acid aqueous solution which is adjusted to a sufficient concentration to extract the rare earth element of interest is fed from line 6 25 as the aqueous phase to the mixer-settler where the steps of mixing the acid aqueous solution (or aqueous phase) 6 with the organic phase 2 scrubbed in scrubber section B, stationary holding and separating them again are repeated in multiple stages, whereby the rare earth element of interest 30 contained in the organic phase 2 is back extracted into the acid aqueous solution (aqueous phase) 6, which is discharged via line 7. The rare earth element of interest is recovered from this acid aqueous solution (aqueous phase) 7. On the other hand, the organic phase 2 from which the rare earth 35 element has been removed by back-extraction is discharged from back-extraction section C and fed back via line 8 to extraction section A for circulation. -3- In the prior art, a mixer-settler is used to construct each of extraction section A, scrubber section B, and back-extraction section C of the multistage continuous extraction system. For example, a mixer-settler of an 5 arrangement as shown in FIG. 6 is commonly used. As shown in FIG. 6, the mixer-settler comprises a plurality of liquid-liquid extraction units k connected in fluid communication, each unit having one mixer chamber f with a propeller e mounted therein and four settler chambers 10 g to j connected in series. In the embodiment of FIG. 6, four liquid-liquid extraction units k are connected in four stages. With this mixer-settler, extraction operation is carried out as follows. The flows of aqueous phase are depicted by solid line arrows and the flows of organic phase 15 depicted by broken line arrows. The aqueous phase and organic phase flow in mixer chamber f where they are stirred and mixed by rotating propeller e, then flow in settler chamber g where they dwell for a certain time, that is, the mixture is kept substantially stationary and gradually 20 separates into aqueous and organic phases again. These aqueous and organic phases successively and moderately transfer from settler chamber g to j while separation between aqueous and organic phases proceeds in progress. In the last settler j, the organic and aqueous phases are separated and 25 discharged whereupon they flow into mixer chambers f of liquid-liquid extraction units k of the subsequent stages. Similar operation is repeated in plural stages (four stages in FIG. 6). As shown by solid line arrows (aqueous phase) and broken line arrows (organic phase) in FIG. 6, the aqueous 30 phase and organic phase flow in counter-current, thereby enhancing the transfer rate of extract between aqueous and organic phases, and achieving a high extraction rate. The multistage continuous extraction system using such mixer-settlers achieves a very high separation efficiency in 35 excess of 99%, enabling separation and recovery of rare earth elements at a very high efficiency. In an example where praseodymium (Pr) and neodymium (Nd) are separated and -4recovered using mono-2-ethylhexyl 2-ethylhexylphosphate (PC-88A by Daihachi Chemical Industry Co., Ltd.), the system should include extraction section A of 32 stages, scrubber section B of 32 stages, and back extraction section C of 8 5 stages, summing to 72 stages in total. That is,. liquid-liquid extraction units k each having five chambers, one mixer chamber f and four settler chambers g to j are connected in 72 stages in total to construct the multistage continuous extraction system. 10 As a consequence, the multistage continuous extraction system for separating and extracting rare earth elements becomes a very large scale installation, requiring a very large footprint. A very large volume of liquid is necessary to fill all the chambers of the system therewith. 15 Accordingly, a size reduction of the system would become a great contribution to cost reduction. It is desirable to reduce the size of the system without any loss of separation efficiency. Citation List 20 Patent Document 1: JP-A 2011-001583 Patent Document 2: JP-A 2011-001584 Patent Document 3: JP-A 2011-001586 Patent Document 4: JP-A 2008-289975 25 SUMMARY OF INVENTION An object of the invention is to provide a liquid-liquid extraction unit which can be reduced in size without sacrificing the efficiency of extraction and separation of rare earth elements, a multistage liquid-liquid 30 extraction apparatus using the unit, and a multistage continuous extraction system comprising a plurality of multistage liquid-liquid extraction apparatus. The inventors have found the following. Liquid-liquid extraction is carried out by feeding an aqueous phase and an 35 organic phase into a tank, contacting them, separating them, and recovering the desired extract from the thus separated aqueous phase and/or organic phase. The aqueous phase in -5bubble form is admitted into the tank from an upper portion thereof, and the organic phase in bubble form is admitted into the tank from a lower portion thereof. The organic phase moving from the lower interior to the upper interior of 5 the tank is contacted with the aqueous phase moving from the upper interior to the lower interior of the tank for transferring the desired substance between aqueous and organic phases. The organic phase is discharged from the upper interior of the tank, and the aqueous phase is 10 discharged from the lower interior of the tank. The desired extract is recovered from the discharged organic and/or aqueous phase. When the bubbly aqueous phase and the bubbly organic phase exchange their position vertically upward and downward, they are effectively contacted with each other so 15 that effective extraction takes place via interfacial reaction, and phase separation proceeds at the same time. Then extraction can be carried out in a small-volume, small-area tank without a need for a large-volume settler chamber as in a mixer-settler, and without any loss of 20 efficiency. However, in the prior art method wherein aqueous and organic phases are contacted and separated solely via vertical upward and downward movements using a well-known spray column or a vertical cylindrical tank used in an 25 extraction unit based on emulsion flow as described in Patent Document 4, reaction cannot catch up at a high flow rate equivalent to the flow rate available in the above-mentioned mixer-settler. Thus reaction must be carried out at a low flow rate in order to maintain an acceptable efficiency, 30 resulting in a loss of processing efficiency. Continuing the research, the inventors have found the following. An extraction/separation tank having a pair of horizontally opposed sidewalls is provided with an aqueous phase inlet at an upper portion of one sidewall, an organic 35 phase inlet at a lower portion of one sidewall, an organic phase outlet at an upper portion of the opposite sidewall, and an aqueous phase outlet at a lower portion of the -6opposite sidewall. The organic and aqueous phases are admitted from the horizontal one sidewall side, move horizontally while exchanging their position vertically upward and downward, and are discharged from the other 5 sidewall side. In this arrangement, a high flow rate equivalent to the flow rate available in the prior art mixer-settler is achievable while maintaining an acceptable efficiency.. The size can be significantly reduced as compared with the prior art mixer-settler. When a multistage 10 continuous extraction system for extracting and separating rare earth elements is constructed, the footprint can be significantly reduced. The volume of liquid necessary for extraction can be significantly reduced. These contribute to a substantial reduction of cost. The invention is predicated 15 on these findings. In one aspect, the invention provides a liquid-liquid extraction unit adapted to contact an aqueous phase with an organic phase, separate them, and recover a desired extract from the thus separated aqueous phase and/or organic phase, 20 comprising an extraction/separation tank for receiving the aqueous phase and the organic phase, having a pair of horizontally opposed sidewalls, an aqueous phase inlet disposed at an upper portion of 25 one sidewall for admitting the aqueous phase in bubble form, an organic phase inlet disposed at a lower portion of one sidewall for admitting the organic phase in bubble form, an organic phase outlet disposed at an upper portion of the other sidewall for discharging the separated organic 30 phase, and an aqueous phase outlet disposed at a lower portion of the other sidewall for discharging the separated aqueous phase. The aqueous phase in bubble form is admitted from the 35 aqueous phase inlet to an upper interior of the tank, the organic phase in bubble form is admitted from the organic phase inlet to an lower interior of the tank, the organic -7phase moving from the lower interior to the upper interior of the tank is contacted with the aqueous phase moving from the upper interior to the lower interior of the tank, the organic phase after contact is discharged and recovered through the 5 organic phase outlet, and the aqueous phase after contact is discharged and recovered through the aqueous phase outlet. The liquid-liquid extraction unit may further comprise a partition disposed between the horizontally opposed sidewalls for dividing the tank into a contact compartment 10 and a separation/recovery compartment, the contact compartment facing the aqueous phase inlet and the organic phase inlet, the separation/recovery compartment facing the organic phase outlet and the aqueous phase outlet, and means disposed above or in an upper portion and below or in a lower 15 portion of the partition for providing fluid communication between the contact compartment and the separation/recovery compartment. In a preferred embodiment, the extraction/separation tank is a parallelepiped tank having a rectangular bottom and 20 a pair of longitudinally opposed sidewalls as the pair of horizontally opposed sidewalls. In another aspect, the invention provides a multistage liquid-liquid extraction apparatus comprising a plurality of liquid-liquid extraction units as defined above, wherein the 25 organic phase outlet of one unit is connected to the organic phase inlet of another unit, and the aqueous phase outlet of the one unit is connected to the aqueous phase inlet of the other unit, so that contact and separation is carried out in multiple stages. 30 In a further aspect, the invention provides a multistage continuous extraction system for extracting a rare earth element, comprising an extraction section for contacting an aqueous phase in the form of an aqueous solution containing rare earth 35 elements with an organic phase containing an extractant, and separating them for thereby extracting at least one rare earth element into the organic phase, and -8a back-extraction section for contacting the organic phase having at least one rare earth element extracted therein with an aqueous phase in the form of an acid aqueous solution and separating them for thereby back extracting the 5 rare earth element into the aqueous phase for recovery, wherein the organic phase after back extraction is discharged from the back-extraction section and fed back to the extraction section for circulation, one or both of the extraction section and the back-extraction section being a 10 multistage liquid-liquid extraction apparatus as defined above. Preferably, the aqueous phase after extraction is discharged from the extraction section and recovered so that the rare earth element which remains in the aqueous phase 15 without being extracted into the organic phase may be recovered. In a still further aspect, the invention provides a multistage continuous extraction system for extracting a rare earth element, comprising 20 an extraction section for contacting an aqueous phase in the form of an aqueous solution containing rare earth elements with an organic phase containing an extractant, and separating them for thereby extracting a first rare earth element into the organic phase, 25 a back-extraction section for contacting the organic phase having the rare earth element extracted therein with an aqueous phase in the form of an acid aqueous solution and separating them for thereby back extracting the first rare earth element into the aqueous phase for recovery, and 30 a scrubber section disposed between the extraction section and the back-extraction section for scrubbing the organic phase discharged from the extraction section by contacting the organic phase with an aqueous phase in the form of an acid aqueous solution having a predetermined acid 35 concentration and separating them for thereby selectively extracting a second rare earth element, which is incidentally contained in the organic phase and should remain in the -9aqueous phase of the extraction section, into the aqueous phase, and for delivering the organic phase after scrubbing to the back-extraction section. The aqueous phase having the second rare earth element 5 extracted from the organic phase in the scrubber section is fed back to the extraction section, the organic phase after back-extraction is discharged from the back-extraction section and fed back to the extraction section for circulation; the aqueous phase discharged from the extraction 10 section Is recovered for thereby recovering a third rare earth element remaining in the aqueous phase without being extracted into the organic phase; at least one of the extraction section, the back-extraction section and the scrubber section being a multistage liquid-liquid extraction 15 apparatus as defined above. ADVANTAGEOUS EFFECTS OF INVENTION The liquid-liquid extraction unit of the invention is of small size and maintains a sufficient extraction 20 efficiency. When a multistage extraction apparatus comprising a plurality of units connected for fluid communication and a multistage continuous extraction system in which a plurality of sections each comprising the multistage extraction apparatus and assigned to different 25 steps are connected for fluid communication are constructed, the footprint can be significantly reduced, and the volume of liquid necessary for extraction can be significantly reduced. These contribute to a substantial reduction of cost required for extraction and separation of rare earth elements. 30 BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic perspective, partially cutaway, view of one exemplary liquid-liquid extraction unit in one embodiment of the invention. 35 FIG. 2 is a schematic perspective, partially cutaway, view of another exemplary liquid-liquid extraction unit in one embodiment of the invention. -10- FIG. 3 is a schematic perspective, partially cutaway, view of a further exemplary liquid-liquid extraction unit in one embodiment of the invention. FIG. 4 is a block diagram of one exemplary multistage 5 continuous extraction system for extraction and separation of rare earth elements, comprising liquid-liquid extraction units, in another embodiment of the invention. FIG. 5 is a block diagram of a prior art multistage continuous extraction system for extraction and separation of 10 rare earth elements. FIG. 6 schematically illustrates a mixer-settler constructing the prior art multistage continuous extraction system. 15 DESCRIPTION OF EMBODIMENTS FIG. 1 schematically illustrates one exemplary liquid-liquid extraction unit in one embodiment of the invention. The unit includes an extraction/separation tank 10 for receiving aqueous and organic phases. Specifically 20 the tank 10 is a parallelepiped vessel having a rectangular bottom, an open top, a pair of horizontally and longitudinally opposed sidewalls 11 and 12, and a pair of horizontally and transversely opposed sidewalls. One sidewall 11 of tank 10 is provided with an aqueous 25 phase inlet 20 in an upper portion thereof and an organic phase inlet 30 in a lower portion thereof. The aqueous phase inlet 20 and organic phase inlet 30 include spray nozzles 21 and 31 projecting into the tank 10. The spray nozzles 21 and 31 are extended through sidewall 11 and connected to an 30 aqueous phase feed line 22 and an organic phase feed line 32, respectively. The aqueous phase is pumped by a pump (not shown) through feed line 22 and admitted into tank 10 via upper spray nozzle 21. Similarly, the organic phase is pumped by a pump (not shown) through feed line 32 and 35 admitted into tank 10 via lower spray nozzle 31. The spray nozzles 21 and 31 have a plurality of orifices in a distal circumferential surface, through which -11the aqueous phase and organic phase are injected in bubble form into the interior of tank 10. The distal shape of the spray nozzle is preferably conical (as spray nozzles 21, 31 are depicted in FIGS. 1 and 2) when a high injection speed is 5 desired. The distal shape of the spray nozzle is not limited to conical shape, and may be flared when spraying of the aqueous and organic phases over a wide area is desired. The other sidewall 12 of tank 10 is provided with an organic phase outlet 40 in an upper portion thereof and an 10 aqueous phase outlet 50 in a lower portion thereof. The organic phase outlet 40 and aqueous phase outlet 50 include discharge ports (not shown) which penetrate through the sidewall 12 and are connected to an organic phase discharge line 41 and an aqueous phase discharge line 51, respectively. 15 By a pump (not shown) connected in organic phase discharge line 41, the organic phase is discharged from the upper interior of tank 10 to organic phase discharge line 41. Similarly, by a pump (not shown) connected in aqueous phase discharge line 51, the aqueous phase is discharged from the 20 lower interior of tank 10 to aqueous phase discharge line 51. In case tank 10 is used alone, the pumps for discharging the organic and aqueous phases through organic phase discharge line 41 and aqueous phase discharge line 51 may be omitted, and the organic and aqueous phases may be discharged as flow 25 under gravity through organic phase discharge line 41 and aqueous phase discharge line 51. Though not critical, it is preferred that the organic phase outlet 40 be disposed at a slightly higher position than the opposed aqueous phase inlet 20. Then the aqueous 30 phase inlet 20 is positioned below the liquid surface, so that the aqueous phase is injected into the liquid. This ensures more effective bubbling of the aqueous phase and more efficient contact with the organic phase. It is also desirable that the total volume of aqueous and organic phases 35 fed to tank 10 be equal to the total volume of aqueous and organic phases discharged from tank 10. As a precaution against the event where the balance of admission and -12discharge is temporarily broken, the other sidewall 12 may be provided with a baffle or L-shaped plate 70 enclosing organic phase outlet 40, and organic phase outlet 40 be positioned below aqueous phase inlet 20, as shown in FIG. 3. 5 Sometimes the organic phase inlet 30 is designed so that the organic phase may be injected from spray nozzle 31 in upward and transverse directions. Preferably, the organic phase inlet 30 is slightly spaced apart from the bottom as shown in FIG. 1 so that the organic phase may be injected 10 from spray nozzle 31 in all vertical and transverse directions. This ensures more effective bubbling of the organic phase and more efficient contact with the aqueous phase. The liquid-liquid extraction unit mentioned above is 15 used to extract and separate rare earth elements, for example. An aqueous phase containing rare earth elements is admitted from aqueous phase inlet 20 in bubble form into an upper interior of tank 10. An organic phase containing an extractant is admitted from organic phase inlet 30 in bubble 20 form into a lower interior of tank 10. The organic and aqueous phases once admitted moves horizontally (or longitudinally) from the one sidewall side to the opposite sidewall side of tank 10 while exchanging their position upward and downward. Due to a difference of specific gravity, 25 the aqueous phase moves downward from above, and the organic phase moves upward from below. While the organic and aqueous phases exchange their position upward and downward, they are effectively contacted mutually whereby the selected rare earth element is extracted from the aqueous phase into the 30 organic phase. While the organic and aqueous phases move moderately toward the opposite sidewall 12 of tank 10, the organic phase and aqueous phase are separated upward and downward. The organic phase having the selected rare earth element extracted therein is discharged from organic phase 35 outlet 40, and the aqueous phase discharged from aqueous phase outlet 50. If the aqueous phase contains a plurality of rare earth elements, at least one of which is not -13extractable with the organic phase, then the unextractable rare earth element is left in the aqueous phase and discharged from aqueous phase outlet 50. In another embodiment, the liquid-liquid extraction 5 unit includes a partition 60 disposed at a horizontal (or longitudinal) intermediate position in extraction/separation tank 10 as shown in FIG. 2. The partition 60 divides the interior of tank 10 into a contact compartment 13 including aqueous phase inlet 20 and organic phase inlet 30 and a 10 separation/recovery compartment 14 including organic phase outlet 40 and aqueous phase outlet 50. A space is left between the lower edge of partition 60 and the bottom of tank 10 for communication for the aqueous phase near the bottom. Also- the height of partition 60 is lower than the sidewalls 15 of tank 10 so that the organic phase may flow across the partition 60 from contact compartment 13 to separation/recovery compartment 14. The upper edge of partition 60 is preferably at a position equal to or slightly higher than spray nozzle 21 of aqueous phase inlet 20, and 20 also preferably at a slightly lower position than the discharge port of organic phase outlet 40. In the embodiment wherein partition 60 is provided to divide the interior of tank 10 into contact compartment 13 and separation/recovery compartment 14, a higher 25 extraction/separation efficiency is expectable. Specifically, once the aqueous phase and organic phase are injected from spray nozzles 21 and 31, partition 60 blocks them and prevents them from directly moving toward outlets 40 and 50; in contact compartment 13, the aqueous and organic phases 30 exchange their position downward and upward, with extraction reaction taking place; the aqueous phase moves into separation/recovery compartment 14 via the lowermost space near the bottom, and the organic phase overflows the top of partition 60 into separation/recovery compartment 14. In 35 separation/recovery compartment 14, further separatory motion takes place between aqueous and organic phases while the impact of jets from nozzles 21 and 31 is substantially -14eliminated by partition 60. Thus a high extraction/separation efficiency is available. The position of partition 60 is not particularly limited and may be determined depending on the volume, 5 horizontal length and height of tank 10, the flow rates of aqueous and organic phases, and the like. In the case of extraction/separation tank 10 having a rectangular bottom as shown in FIGS. 1 and 2, partition 60 is preferably disposed at any position between the longitudinal center of the bottom 10 and the one sidewall (liquid inlet side) of tank 10 so that separation/recovery compartment 14 may have a volume equal to or larger than the volume of contact compartment 13. Then separation/recovery compartment 14 assuming a nearly stationary state offers a longer dwell time, achieving more 15 effective separation between aqueous and organic phases. It is noted that although spray nozzles 21 and 31 are used to inject the aqueous and organic phases in bubble form in the embodiments of FIGS. 1 and 2, any means of admitting bubbles of the aqueous and organic phases into tank 10 may be 20 used instead of the spray nozzles. Also, although spaces are provided below and above partition 60 for fluid communication in the embodiment of FIG. 2, it is acceptable that partition 60 is extended from the top to the bottom of tank 10 and perforated in lower and upper portions thereof with ports for 25 fluid communication. Further, the shape of tank 10 is not limited to FIGS. 1 and 2. Any tank shape is acceptable as long as liquid phases move vertically up and down like a spray column, or as long as aqueous phase and organic phase move vertically up and down and move horizontally whereby the 30 aqueous and organic phases admitted from one sidewall side at upper and lower positions are discharged from the opposite sidewall side at inverse (lower and upper) positions. The liquid-liquid extraction unit in one embodiment of the invention may be used to construct a multistage 35 liquid-liquid extraction apparatus. There are provided a plurality of liquid-liquid extraction units, which are connected such that the organic phase discharge line 41 of -15one unit is connected to the organic phase feed line 32 of another unit, and the aqueous phase discharge line 51 of the one unit is connected to the aqueous phase feed line 22 of the other unit. Then extraction operation is performed in 5 multiple stages. When the step of extracting a rare earth element in the aqueous phase into the organic phase, the step of scrubbing the organic phase, and the step of back extracting the rare earth element from the organic phase for recovery are continuously carried out, at least one (one, two 10 or all) of the extraction section, the scrubber section and the back-extraction section may be a multistage liquid-liquid extraction apparatus comprising liquid-liquid extraction units. As mentioned above, the liquid-liquid extraction unit 15 in one embodiment of the invention comprises an extraction/separation tank 10, an aqueous phase inlet 20 in an upper portion of one sidewall, an organic phase inlet 30 in a lower portion of one sidewall, an organic phase outlet 40 in an upper portion of the opposite sidewall, and an 20 aqueous phase outlet 50 in a lower portion of the opposite sidewall, wherein the organic and aqueous phases are admitted in bubble form from one sidewall, move horizontally (or longitudinally) while exchanging their position upward and downward, and are discharged from the opposite sidewall. 25 While the bubbly aqueous phase and the bubbly organic phase exchange their position upward and downward, an effective mutual contact occurs therebetween. Then effective extraction takes place due to interfacial reaction, and phase separation proceeds at the same time. Extraction and 30 separation operation can be performed in a small volume and small area without a loss of efficiency, and without a need for a large volume settler chamber as in a prior art mixer settler. In the liquid-liquid extraction unit of the invention, 35 not only the organic phase and the aqueous phase exchange their position upward and downward, but also they move vertically and horizontally before they are discharged out. -16- The unit maintains an acceptable efficiency and achieves a high flow rate comparable to the flow rate in the prior art mixer-settler. The size of the unit is significantly small as compared with the prior art mixer-settler. When a 5 multistage extraction apparatus comprising a plurality of units and a multistage continuous extraction system in which a plurality of multistage extraction apparatus are connected for fluid communication are constructed, the footprint can be significantly reduced, and the volume of liquid necessary for 10 extraction can be significantly reduced. These contribute to a substantial reduction of cost required for extraction and separation of rare earth elements. EXAMPLE 15 Examples of the invention are given below by way of illustration and not by way of limitation. Comparative Example A prior art multistage counterflow mixer-settler as 20 shown in FIGS. 5 and 6 was used to carry out extraction and separation of rare earth elements (praseodymium and neodymium). The multistage counterflow mixer-settler system of FIG. 5 includes an extraction section A of 32 stages, a scrubber 25 section B of 32 stages, and a back-extraction section C of 8 stages. One stage is constructed by the mixer-settler of FIG. 6 in which the mixer chamber f is dimensioned 80 mm (W) x 80 mm (D) x 200 mm (H), the settler consisting of four chambers g to j is dimensioned 320 mm (W) x 80 mm (D) x 200 mm (H), 30 and one stage is thus dimensioned 400 mm (W) x 80 mm (D) x 200 mm (H). Extraction section A having 32 stages connected is combined with scrubber section B having 32 stages connected, to construct an extraction section plus scrubber section A+B of 64 stages which is dimensioned 400 mm x 5120 35 mm x 200 mm (H). The volume of liquid necessary to fill the extraction section plus scrubber section A+B was 328 L. -17- A solution was prepared by dissolving extractant PC-88A (mono-2-ethylhexyl 2-ethylhexylphosphate) in kerosene in a concentration of 0.5 mol/L and used as the organic phase. A mixed aqueous solution, 1000 L, containing praseodymium and 5 neodymium in a molar ratio Pr:Nd of 1:1 and a concentration of 0.1 mol/L of Pr+Nd was prepared and used as the aqueous phase. In FIG. 5, the aqueous phase from line 1 was fed at a flow rate of 6 L/hr, the organic phase from line 2 was fed at a flow rate of 19 L/hr, and a 4 mol/L sodium hydroxide aqueous 10 solution from line 3 was fed at a flow rate of 1.5 L/hr to extraction section A where neodymium in the aqueous phase was extracted into the organic phase. The organic phase was fed to scrubber section B while the aqueous phase was discharged through line 5 at a flow rate of 8.4 L/hr and recovered. In is scrubber section B, a 5.5 mol/L hydrochloric acid aqueous solution from line 4 was fed at a flow rate of 0.9 L/hr as the aqueous phase, whereby the organic phase 2 is scrubbed in that praseodymium (which was contained in the organic phase and which should essentially remain in the aqueous phase in 20 extraction section A) was selectively extracted into the hydrochloric acid solution (aqueous phase) 4. The organic phase 2 is fed to back-extraction section C. On the other hand, the hydrochloric acid solution (aqueous phase) having selectively extracted therein the praseodymium (to remain in 25 the aqueous phase in extraction section A) is discharged through line 9 and fed back to line 1. Next, a 5.5 mol/L hydrochloric acid aqueous solution from line 6 was fed at a flow rate of 1.2 L/hr as the aqueous phase to back-extraction section C, where neodymium was back extracted from the organic 30 phase to the hydrochloric acid aqueous solution (aqueous phase), which is discharged through line 7 at a flow rate of 1.2 L/hr and recovered. On the other hand, the organic phase is discharged from back-extraction section C through line 8 and fed back to extraction section A, completing circulation. 35 The extraction and separation operation from extraction section A to back-extraction section C was performed in an environment at a temperature 35"C. -18- After the extraction and separation operation, the concentration of praseodymium and neodymium in the aqueous phase recovered from line 5 and the hydrochloric acid solution recovered from line 7 was measured by an ICP atomic 5 emission spectrometer. The hydrochloric acid solution recovered from line 7 had a neodymium concentration of 0.03 mol/L and a neodymium purity (Nd/(Pr+Nd)) of 99.5%. The aqueous phase recovered from line 5 had a praseodymium concentration of 0.03 mol/L and a praseodymium purity 10 (Pr/(Pr+Nd)) of 99.6%. Example A multistage continuous extraction system was constructed as shown in FIG. 4. The system construction was 15 the same as in FIG. 5 in Comparative Example except that extraction section A and scrubber section B were constructed using the liquid-liquid extraction units as shown in FIG. 2, and an alkali mixing section D for mixing a sodium hydroxide aqueous solution 3 with the organic phase 2 was disposed 20 upstream of extraction section A. The back-extraction section C of 8 stages was constructed using a mixer-settler as in Comparative Example. The alkali mixing section D is a vessel dimensioned 80 mm x 80 mm x 200 mm and equipped with an impeller where the sodium hydroxide aqueous solution from 25 line 3 is uniformly mixed with the organic phase 2 before the liquid is discharged or fed to extraction section A. The liquid-liquid extraction unit shown in FIG. 2 is dimensioned 120 mm (W) x 80 mm (D) x 200 mm (H). A partition 60 of 5 mm x 80 mm x 170 mm (H) is disposed at a distance of 30 60 mm from one sidewall and spaced 5 mm apart from the bottom to divide the tank 10 into a contact compartment 13 and a separation/recovery compartment 14 of substantially the same volume. Each of spray nozzles 21 and 31 is a conical tube with a closed tip having 30 orifices (diameter 1 mm) 35 perforated in its circumferential surface. An extraction section A of 32 stages is constructed by connecting 32 -19liquid-liquid extraction units, and a scrubber section B of 32 stages is constructed by connecting 32 liquid-liquid extraction units. The extraction section A constructed by a multistage 5 liquid-liquid extraction apparatus comprising 32 liquid-liquid extraction units connected is combined with the scrubber section B constructed by a multistage liquid-liquid extraction apparatus comprising 32 liquid-liquid extraction units connected, to construct an extraction section plus 10 scrubber section A+B of 64 stages which is dimensioned 120 mm x 5120 mm x 200 mm (H). The footprint of this extraction section plus scrubber section A+B was 3/10 of that in Comparative Example. The volume of liquid necessary to fill the extraction section plus scrubber section A+B was 98 L. 15 The necessary liquid volume was also 3/10 of that in Comparative Example. Next, using the multistage continuous extraction system of FIG. 4, extraction and separation of praseodymium and neodymium was carried out as in Comparative Example. 20 Since the solutions fed from the lines and the flow rates of admission and discharge were the same as in Comparative Example, the same reference characters as in Comparative Example (FIG. 5) are used in FIG. 4 and the description of extraction/separation operation is omitted. 25 The concentration of praseodymium and neodymium in the aqueous phase recovered from line 5 and the hydrochloric acid solution recovered from line 7 was measured by the ICP atomic emission spectrometer. The hydrochloric acid solution recovered from line 7 had a neodymium concentration of 0.03 30 mol/L and a neodymium purity (Nd/(Pr+Nd)) of 99.5%. The aqueous phase recovered from line 5 had a praseodymium concentration of 0.03 mol/L and a praseodymium purity (Pr/(Pr+Nd)) of 99.6%. It was proven that separation and extraction rates equal to Comparative Example were available. 35 It has been demonstrated that using the liquid-liquid extraction unit of the invention, a multistage liquid-liquid extraction apparatus and system can be reduced in size while -20maintaining a satisfactory extraction efficiency. The footprint can be significantly reduced. The volume of liquid necessary for processing can be significantly reduced. The cost required for extraction and separation of rare earth 5 elements can be significantly reduced. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply -the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. -21-
    权利要求:
    Claims (7)
    [1] 1. A liquid-liquid extraction unit adapted to contact an aqueous phase with an organic phase, separate them, and 5 recover a desired extract from the thus separated aqueous phase and/or organic phase, comprising an extraction/separation tank for receiving the aqueous phase and the organic phase, having a pair of horizontally opposed sidewalls, 10 an aqueous phase inlet disposed at an upper portion of one sidewall for admitting the aqueous phase in bubble form, an organic phase inlet disposed at a lower portion of one sidewall for admitting the organic phase.in bubble form, an organic phase outlet disposed at an upper portion 15 of the other sidewall for discharging the separated organic phase, and an aqueous phase outlet disposed at a lower portion of the other sidewall for discharging the separated aqueous phase, 20 wherein the aqueous phase in bubble form is admitted from the aqueous phase inlet to an upper interior of the tank, the organic phase in bubble form is admitted from the organic phase inlet to an lower interior of the tank, the organic phase moving from the lower interior to 25 the upper interior of the tank is contacted with the aqueous phase moving from the upper interior to the lower interior of the tank, the organic phase after contact is discharged and recovered through the organic phase outlet, and the aqueous 30 phase after contact is discharged and recovered through the aqueous phase outlet.
    [2] 2. The unit of claim 1, further comprising a partition disposed between the horizontally opposed 35 sidewalls for dividing the tank into a contact compartment and a separation/recovery compartment, the contact compartment facing the aqueous phase inlet and the organic -22- phase inlet, the separation/recovery compartment facing the organic phase outlet and the aqueous phase outlet, and means disposed above or in an upper portion and below or in a lower portion of the partition for providing fluid 5 communication between the contact compartment and the separation/recovery compartment.
    [3] 3. The unit of claim 1 or 2 wherein the extraction/separation tank is a parallelepiped tank having a 10 rectangular bottom and a pair of longitudinally opposed sidewalls as the pair of horizontally opposed sidewalls.
    [4] 4. A multistage liquid-liquid extraction apparatus comprising a plurality of liquid-liquid extraction units as 15 set forth in any one of claims 1 to 3, wherein the organic phase outlet of one.unit is connected to the organic phase inlet of another unit, and the aqueous phase outlet of the one unit is connected to the aqueous phase inlet of the other unit, so that contact and separation is carried out in 20 multiple stages.
    [5] 5. A multistage continuous extraction system for extracting a rare earth element, comprising an extraction section for contacting an aqueous phase 25 in the form of an aqueous solution containing rare earth elements with an organic phase containing an extractant, and separating them for thereby extracting at least one rare earth element into the organic phase, and a back-extraction section for contacting the organic 30 phase having at least one rare earth element extracted therein with an aqueous phase in the form of an acid aqueous solution and separating them for thereby back extracting the rare earth element into the aqueous phase for recovery, wherein the organic phase after back extraction is 35 discharged from the back-extraction section and fed back to the extraction section for circulation, -23- one or both of the extraction section and the back-extraction section being a multistage liquid-liquid extraction apparatus as set forth in claim 4. 5
    [6] 6. The system of claim 5 wherein the aqueous phase after extraction is discharged from the extraction section and recovered so that the rare earth element which remains in the aqueous phase without being extracted into the organic phase may be recovered. 10
    [7] 7. A multistage continuous extraction system for extracting a rare earth element, comprising an extraction section for contacting an aqueous phase in the form of an aqueous solution containing rare earth 15 elements with an organic phase containing an extractant, and separating them for thereby extracting a first rare earth element into the organic phase, a back-extraction section for contacting the organic phase having the rare earth element extracted therein with an 20 aqueous phase in the form of an acid aqueous solution and separating them for thereby back extracting the first rare earth element into the aqueous phase for recovery, and a scrubber section disposed between the extraction section and the back-extraction section for scrubbing the 25 organic phase discharged from the extraction.section by contacting the organic phase with an aqueous phase in the form of an acid aqueous solution having a predetermined acid concentration and separating them for thereby selectively extracting a second rare earth element, which is incidentally 30 contained in the organic phase and should remain in the aqueous phase of the extraction section, into the aqueous phase, and for delivering the organic phase after scrubbing to the back-extraction section, wherein the aqueous phase having the second rare earth 35 element extracted from the organic phase in the scrubber section is fed back to the extraction section, the organic phase after back-extraction is discharged from the -24- back-extraction section and fed back to the extraction section for circulation, the aqueous phase discharged from the extraction section is recovered for thereby recovering a third rare 5 earth element remaining in the aqueous phase without being extracted into the organic phase, at least one of the extraction section, the back-extraction section and the scrubber section being a multistage liquid-liquid extraction apparatus as set forth in 10 claim 4. -25-
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    同族专利:
    公开号 | 公开日
    BR102013000949A2|2013-10-08|
    CN103203120B|2016-01-06|
    CN103203120A|2013-07-17|
    RU2013100950A|2014-07-20|
    KR20130083850A|2013-07-23|
    PH12013000008B1|2014-08-04|
    CA2802054A1|2013-07-13|
    US20160304986A1|2016-10-20|
    JP5720583B2|2015-05-20|
    EP2614868A1|2013-07-17|
    AU2013200062B2|2015-05-28|
    BR102013000949B1|2021-05-11|
    MY157324A|2016-05-31|
    RU2621550C2|2017-06-06|
    US20130183208A1|2013-07-18|
    JP2013144270A|2013-07-25|
    CA2802054C|2020-03-10|
    EP2614868B1|2022-03-02|
    ZA201300202B|2013-08-28|
    US10407752B2|2019-09-10|
    PH12013000008A1|2014-08-04|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US2361780A|1942-01-12|1944-10-31|Shell Dev|Extraction process|
    US2631780A|1949-09-12|1953-03-17|Branner Samuel|Ball controlled register|
    US2646346A|1950-02-27|1953-07-21|Atomic Energy Commission|Multistage mixer-settler apparatus|
    BE564897A|1957-01-10||||
    JPS4827978A|1971-08-13|1973-04-13|||
    NO135084C|1974-07-03|1977-02-09|Sjeldne Jordarter Forskning||
    US4039389A|1975-11-03|1977-08-02|Uop Inc.|Liquid-liquid extraction apparatus|
    DE3064641D1|1979-09-21|1983-09-29|Rhone Poulenc Chim Base|Process for global recovery of uranium, rare earth metals, thorium and yttrium from an acid solution|
    DE3133314A1|1981-08-22|1983-03-10|Hoechst Ag, 6000 Frankfurt|"DEVICE FOR DISPERGING A SECOND PHASE IN A FIRST PHASE"|
    FR2562059B1|1984-04-02|1989-12-01|Rhone Poulenc Spec Chim|PROCESS FOR SEPARATING RARE EARTH BY LIQUID-LIQUID EXTRACTION|
    FR2594429A1|1986-02-14|1987-08-21|Rhone Poulenc Chimie|METHOD FOR REMOVING LEAD FROM RARE EARTHS|
    CN86201198U|1986-03-10|1986-12-31|核工业部北京第五研究所|Mixing and clearing unit|
    US5030424A|1989-04-03|1991-07-09|Alcan International Limited|Recovery of rare earth elements from Bayer process red mud|
    JPH06106002A|1992-09-29|1994-04-19|Takeshi Amano|Extractor having rotating perforated plates|
    CA2256764A1|1996-06-26|1997-12-31|Henkel Corporation|Process for the recovery of precious metal values from aqueous ammoniacal thiosulfate leach solutions|
    RU2253499C2|2000-10-23|2005-06-10|Юоп Ллк|Device for a liquid by a liquid extraction|
    FI116611B|2004-06-10|2006-01-13|Outokumpu Oy|Process and apparatus for purifying aqueous solution residues from an aqueous solution, which is insoluble in water solutions|
    CN101219289A|2007-01-12|2008-07-16|有研稀土新材料股份有限公司|Mixed settler extractor|
    JP5565719B2|2007-05-23|2014-08-06|独立行政法人日本原子力研究開発機構|Continuous liquid-liquid extraction device using emulsion flow|
    JP5305382B2|2008-09-30|2013-10-02|独立行政法人日本原子力研究開発機構|Counterflow emulsion flow continuous liquid-liquid extraction device|
    JP5299914B2|2009-06-17|2013-09-25|信越化学工業株式会社|Extraction and separation method of rare earth elements|
    JP5392828B2|2009-06-17|2014-01-22|信越化学工業株式会社|Extraction and separation method of rare earth elements|
    JP5499353B2|2009-06-17|2014-05-21|信越化学工業株式会社|Extraction and separation method of rare earth elements|
    AU2010202408B2|2009-06-17|2014-12-18|Shin-Etsu Chemical Co., Ltd.|Method for extracting and separating rare earth elements|
    CN202061409U|2011-05-03|2011-12-07|宜兴新威利成稀土有限公司|Extraction slot with double mixing chambers|JP2015199981A|2014-04-07|2015-11-12|信越化学工業株式会社|Method and device for extracting/removing rare earth metal ion in plating solution|
    CN106999796B|2014-10-24|2020-09-25|生命科技股份有限公司|Liquid-liquid sample purification system with acoustic precipitation|
    CN104771932B|2015-03-25|2016-04-06|合肥通用机械研究院|A kind of centrifugal extractor external reflux at the corresponding levels|
    KR101777228B1|2016-08-05|2017-09-26|한전원자력연료 주식회사|Module type extraction column|
    CN106947862B|2017-06-01|2018-05-29|烟台凯实工业有限公司|A kind of new-type degreasing unit for rare earth feed liquid|
    CN107058729B|2017-06-01|2018-05-29|江苏永超磁性材料有限公司|A kind of horizontal degreasing unit for rare earth feed liquid|
    CN107267764B|2017-07-31|2018-12-04|赣州市恒源科技股份有限公司|A kind of neodymium iron boron waste material abstraction impurity removal device|
    JP6551550B2|2018-01-09|2019-07-31|信越化学工業株式会社|Extraction method of rare earth metal ions in plating solution|
    JP6483886B2|2018-03-30|2019-03-13|国立研究開発法人日本原子力研究開発機構|Emulsion flow generation and extinguishing device and method for producing specific substance using the same|
    CN109621485A|2018-12-13|2019-04-16|中石化炼化工程（集团）股份有限公司|A kind of device and method of solvent extraction product|
    CN111020238A|2019-12-10|2020-04-17|陈西华|Rare earth solution processing apparatus|
    CN111659156A|2020-06-18|2020-09-15|徐州生物工程职业技术学院|Continuous countercurrent extraction method and equipment for traditional Chinese medicine|
    CN112159905A|2020-09-15|2021-01-01|中稀稀土新材料有限公司|Extraction device and extraction method for multi-level circulating high-purity lutetium|
    法律状态:
    2015-09-24| FGA| Letters patent sealed or granted (standard patent)|
    优先权:
    申请号 | 申请日 | 专利标题
    JP2012-005224||2012-01-13||
    JP2012005224A|JP5720583B2|2012-01-13|2012-01-13|Liquid-liquid extraction apparatus, multistage liquid-liquid extraction apparatus using the same, and multistage continuous extraction apparatus for rare earth elements|
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