Tantalum-niobium extraction device and preparation method of high-selectivity tantalum-niobium extraction agent thereof

Abstract

The invention provides a tantalum-niobium extraction device and a high-selectivity tantalum-niobium extraction agent preparation method thereof, and relates to the technical field of hydrometallurgy. The tantalum-niobium extraction device comprises a base, an extraction mechanism and an auxiliary mechanism; a heating seat is mounted above the base, an extraction barrel is mounted in the heating seat, a top plate is mounted at the top of the extraction barrel through bolts, and an air cylinder is mounted at the top of the top plate through bolts. According to the scheme, recycled metal parts (waste metal parts, electronic products and other waste recycled materials containing tantalum and niobium) are placed in the storage barrel, an extraction solvent is stored in the extraction barrel, and raw materials and the solvent are mixed through the storage barrel which ascends and descends in a reciprocating mode; one turning plate can be controlled in a linkage manner, and four linkage plates can be controlled in a linkage manner to perform clockwise and anticlockwise reciprocating turning motion, so that a solvent in the extraction barrel can be stirred in the turning process, and sufficient mixing and contact of the solvent and raw materials are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrometallurgy, and in particular to a tantalum and niobium extraction device and a preparation method of a highly selective tantalum and niobium extractant. Background Art

[0002] Tantalum and niobium are important strategic metals, which are widely used in the fields of electronics, aerospace, etc. Traditional tantalum and niobium separation processes mostly adopt solvent extraction method, and the tantalum and niobium components in the material to be processed are extracted by hydrometallurgy. Since tantalum and niobium are important strategic metals, in addition to extraction from concentrates, the tantalum and niobium substances in some industrial waste metals and recycled metal electronic devices also need to be extracted during recycling. Therefore, hydrometallurgical extraction can be applied to tantalum and niobium extraction in multiple directions.

[0003] Publication No.: CN220926882U provides a tantalum and niobium two-phase extraction tank, which includes a mounting frame. An extraction tank is arranged in the mounting opening formed inside the mounting frame. A discharge pipe is arranged at the discharge port formed at the lower end of the extraction tank. A solenoid valve I is connected in series in the middle of the discharge pipe. A feed pipe is arranged at the feed port formed at the upper end of the extraction tank. A solenoid valve II is connected in series in the middle of the feed pipe. A stirring mechanism is arranged inside the extraction tank. By stirring the tantalum and niobium raw materials and the solvent while scraping the tantalum and niobium raw materials on the inner wall of the extraction tank, it can effectively prevent the tantalum and niobium raw materials from adhering to the inner wall of the extraction tank, so as to comprehensively extract tantalum and niobium.

[0004] However, in actual operation of the above device, the extraction raw materials and various solvents are extracted inside a carrier. In this way, the extracted tantalum and niobium substances are still mixed with the raw materials. At the same time, there are too many impurities in the recycled raw materials, and the co-extraction phenomenon of impurity metals (such as iron and titanium) is significant, resulting in low extraction efficiency and poor extraction effect.

[0005] Therefore, it is necessary to provide a tantalum and niobium extraction device and a preparation method of a highly selective tantalum and niobium extractant to solve the above technical problems. Summary of the Invention

[0006] The present invention provides a tantalum and niobium extraction device and a preparation method of a highly selective tantalum and niobium extractant, which solve the technical problems that the co-extraction phenomenon of impurity metals (such as iron and titanium) in the recycled raw materials is significant in the related technology, resulting in low extraction efficiency and poor extraction effect.

[0007] To solve the above technical problems, a tantalum and niobium extraction device provided by the present invention includes a base, an extraction mechanism and an auxiliary mechanism;

[0008] A heating base is installed above the base. An extraction barrel is installed inside the heating base. The top of the extraction barrel is installed with a top plate through bolts. The top of the top plate is installed with a cylinder through bolts. A vertically liftable lifting rod is installed inside the cylinder;

[0009] The extraction mechanism includes a storage barrel, the top of the storage barrel is installed with a top frame through bolts, a middle plate is fixedly arranged on the inner wall of the top frame, a rotating seat is installed at the middle position of the top of the middle plate through bolts, a flange seat is installed at the bottom end of the lifting rod through bolts, a mounting seat is fixedly arranged on the side wall of the top frame, and a guide wheel is rotatably connected inside the mounting seat;

[0010] The auxiliary mechanism includes a flap, a through connection groove is formed inside the flap, two first positioning seats are installed at the inner bottom of the extraction barrel, sleeves are fixedly arranged inside both of the two first positioning seats, rotating shafts are fixedly arranged on both sides of the flap, torsion springs are sleeved on the outer walls of the two rotating shafts and inside the two sleeves, second positioning seats are installed at the inner bottom of the extraction barrel and on both sides of the flap, a linkage plate is rotatably connected inside the second positioning seat, a through hole is formed inside the linkage plate, and a connection wheel is rotatably connected to the side wall of the linkage plate.

[0011] Preferably, both of the two rotating shafts are rotatably connected to the axles of the two sleeves through bearings, both sides of the torsion spring are respectively in contact with the inner wall of the sleeve and the rotating shaft, and the connection wheel is slidably connected with the connection groove.

[0012] Preferably, the flange seat and the rotating seat are rotatably connected, and the bottom surface of the storage barrel is in contact with the upper surface of the flap.

[0013] Preferably, a scraping mechanism is further included, the scraping mechanism includes positioning plates installed on both sides of the lifting rod and above the flange seat, a scraping ring is installed at the inner bottom of the storage barrel, and connecting plates are fixedly arranged on both sides of the inner wall of the scraping ring;

[0014] Both of the two positioning plates are slidably connected with the two connecting plates through "T"-shaped blocks.

[0015] Preferably, a corrugated plate is fixedly arranged on the inner wall of the storage barrel and in the vertical direction of the guide wheel, a discharge pipe is installed at the central axis of the storage barrel, sealing plates are rotatably installed above the storage barrel and on both sides of the top plate, and both the upper and lower sides of the corrugated plate are of inclined surface structures.

[0016] Preferably, an air-increasing mechanism is further included. The air-increasing mechanism includes a positioning frame installed on one side of the cylinder. An extrusion cylinder is installed inside the positioning frame. A piston rod is slidably connected inside the extrusion cylinder. A return spring is sleeved on the outer wall of the piston rod. A first one-way valve is installed at the inner bottom of the extrusion cylinder. A second one-way valve is installed on the side of the extrusion cylinder and on one side of the first one-way valve. A connecting pipe is installed at the air outlet end of the second one-way valve. Two bottom plates are installed at the inner bottom of the storage bucket through bolts. An annular pipe is installed inside the two bottom plates. Four air outlet pipes are installed on the outer wall of the annular pipe. The top end of the lifting rod is installed with a lifting plate through bolts.

[0017] Preferably, the upper surface of the lifting plate is mutually attached to the upper surface of the piston rod. The first one-way valve allows one-way passage from outside to inside, and the second one-way valve allows one-way passage from inside to outside.

[0018] Preferably, the air outlet end of the connecting pipe penetrates through the inside of the top plate and the bottom plate and is hermetically installed with the annular pipe. The upper and lower ends of the return spring are in contact with the piston rod and the extrusion cylinder respectively.

[0019] A preparation method of a highly selective tantalum-niobium extractant includes the following steps:

[0020] S1: Synthesis of bisquaternary ammonium salt intermediate

[0021] React N,N'-dimethylpiperazine with brominated long-chain alkane (such as 1-bromododecane) in ethanol by refluxing for 12 hours to generate bisquaternary ammonium salt bromide.

[0022] Replace the bromide ion with nitrate radical through an ion exchange resin (such as D201 strong basic anion resin) to obtain the bisquaternary ammonium salt nitrate intermediate.

[0023] CH3-N(CH2CH2N + CH3)2+2C 12 H 25 Br 乙醇,回流 →[C 12 H 25 N + CH2CH2N + C 12 H 25 ·2Br+C3H8

[0025] Condition: Ethanol solvent, reflux for 12 hours.

[0026] S2: Phosphonate functionalization modification

[0027] React the intermediate with triethyl phosphite in tetrahydrofuran, control the temperature at 60 - 80 °C, and add a catalyst (such as aluminum chloride) to generate a phosphonated bisquaternary ammonium salt precursor.

[0028] Add long-chain fatty alcohol (such as n-octanol) for transesterification reaction, adjust the pH to neutral, and produce the crude target extractant.

[0029] [R1N + CH2CH2N + R2]·2NO 3- +2PO(OEt)2→

[0030] AlCl3,60-80℃ [R1N + CH2CH2N + R2]·2NO 3- ·(PO(OEt)2)2

[0031] Condition: Tetrahydrofuran (THF) solvent, catalyzed by aluminum chloride.

[0032] S3: Introduction of long-chain fatty alcohol in transesterification reaction

[0033] Mix the phosphoric acid esterified bisquaternary ammonium salt precursor with excessive n-octanol, add the catalyst PTSA, heat to 80 - 100 °C, stir for 2 - 3 hours, remove the generated short-chain alcohol (such as ethanol) by distillation, cool to room temperature after completion, wash the organic phase with saturated sodium bicarbonate solution to remove the residual catalyst, and then remove the unreacted n-octanol by vacuum distillation.

[0034] [R1N + CH2CH2N + R2]·2NO 3- ·(PO(OEt)2)2+2C8H 17 OH→

[0035] p H=7[R1N + CH2CH2N + R2]·2NO 3- ·(PO(OC8H 17 )2)2+2EtOH

[0036] Condition: Neutral pH, excessive fatty alcohol, catalyst PTSA, temperature 80 - 100 °C.

[0037] S4: Synthesis of diester quaternary ammonium salt surfactant

[0038] Synthesis of intermediate (Ⅰ)

[0039] Nylon acid (HOOC-(CH2) n -COOH)+ epichlorohydrin (acidic cation resin, 130 °C) → dibasic acid ester intermediate (Cl-OOC-(CH2) n -COO-Cl)

[0040] Condition: epichlorohydrin as solvent, reacting for 12 hours

[0041] Add adipic acid and excessive epichlorohydrin (molar ratio 1:3) into the reaction kettle, then add acidic cation exchange resin (catalyst, dosage is 5% of the total mass). Heat to 130 - 140 °C, stir and react for 12 hours. Finally, filter to remove the catalyst, and recover the unreacted epichlorohydrin by vacuum distillation to obtain the white solid intermediate (Ⅰ).

[0042] Synthesis of the final product (Ⅱ)

[0043] Dicarboxylic acid ester intermediate + 2C12H25N(CH3)2 →

[0044] Na2CO3, acetone Diester quaternary ammonium salt surfactant + 2HCl

[0045] Condition: acetone as solvent, refluxing for 5 hours

[0046] Dissolve the intermediate (Ⅰ) in acetone, add excessive long-chain alkyl tertiary amine (molar ratio 1:2.2), add sodium carbonate (molar ratio is 2 times that of the intermediate) to neutralize the generated HCl, heat to 60 - 70 °C, stir and react for 5 hours. Filter to remove the generated NaCl, and remove acetone by vacuum distillation. Recrystallize the crude product with n-hexane to obtain the final product, diester quaternary ammonium salt surfactant (Ⅱ).

[0047] S5: Synthesis of tertiary amine extractant

[0048] The diester quaternary ammonium salt surfactant is prepared by esterification reaction of dicarboxylic acid and epichlorohydrin to form an intermediate, and then quaternization reaction with long-chain alkyl tertiary amine. This surfactant has a diester group structure, enhancing its hydrophobicity and interfacial activity.

[0049] C8H 17 Br + α-methylbenzylamine KOH,乙醇 C8H 17 N(CH2C6H5)CH3 + KBr

[0050] Condition: base catalysis, heating under reflux

[0051] Add α-methylbenzylamine and 1-bromooctane (molar ratio 1:1.2) into the three-necked flask. Add ethanol as the solvent, and add KOH (molar ratio is 1.5 times that of alkyl bromide). Heat to ethanol reflux (80 - 90 °C), stir and react for 8 - 10 hours. After the reaction, cool to room temperature, filter to remove the KBr precipitate. Remove ethanol by vacuum distillation, and purify the crude product by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 10:1). Collect the target component to obtain a colorless liquid tertiary amine extractant.

[0052] S6: Purification and Modification

[0053] Unreacted fatty alcohol and by-products were removed by silica gel column chromatography, and the target components were collected.

[0054] The specific steps were to dissolve the crude reaction product in a small amount of dichloromethane, separate the target product using silica gel column chromatography, with the eluent being dichloromethane and methanol, collect the target components, and remove the solvent by vacuum distillation.

[0055] Antioxidants (such as 2,6-di-tert-butyl-p-cresol) were added to improve the chemical stability of the extractant.

[0056] The specific operation steps were to add 0.1%-0.5% of antioxidant (such as BHT) to the purified extractant and stir until completely dissolved to ensure the chemical stability of the extractant.

[0057] Compared with the related technologies, the tantalum-niobium extraction device and the preparation method of its highly selective tantalum-niobium extractant provided by the present invention have the following beneficial effects:

[0058] Through the design of the inner and outer storage barrels and the extraction barrel, the recycled metal parts (waste metal parts, electronic products, and all other waste recyclables containing tantalum and niobium) were placed in the storage barrel, and the extraction solvent was stored in the extraction barrel. The raw materials and the solvent were mixed by the reciprocating lifting storage barrel. And when the storage barrel was lifting, a flap could be linked to control four linkage plates to perform reciprocating flipping motions clockwise and counterclockwise. In this way, the solvent in the extraction barrel could be agitated internally during the flipping process, ensuring full mixing and contact between the solvent and the raw materials. Secondly, during the flipping process of the linkage plates, the solvent could form a flipping eddy along the inner wall of the through holes through the flipping through holes. Therefore, such a design achieved efficient mixing, full extraction, and at the same time, could perform extraction in zones to ensure that the raw materials and the extract could be separately distinguished. Brief Description of the Drawings

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0060] Figure 1 It is the best structural schematic diagram provided by the present invention;

[0061] Figure 2 It is the bottom view structural schematic diagram provided by the present invention;

[0062] Figure 3 For Figure 1Schematic cross-sectional structure diagram of the extraction barrel shown;

[0063] Figure 4 is Figure 3 Schematic structure diagram of the extraction mechanism and scraping mechanism shown;

[0064] Figure 5 is Figure 4 Schematic bottom view structure diagram shown;

[0065] Figure 6 Schematic bottom structure diagram of the auxiliary mechanism and gas-increasing mechanism after the extraction barrel is cut open provided by the present invention;

[0066] Figure 7 Schematic cross-sectional structure diagram of the first positioning seat and the sleeve provided by the present invention;

[0067] Figure 8 Initial schematic diagram of the extraction work of the storage barrel provided by the present invention, where (a) represents the schematic diagram of the working state of the bottom of the storage barrel and the upper surface of the flap being fitted, and (b) is the three-dimensional diagram of the initial state of the auxiliary mechanism;

[0068] Figure 9 is Figure 8 Schematic diagram of the extraction work of the storage barrel shown, where (c) represents the schematic diagram of the working state of the control flap driving the linkage plate to flip when the storage barrel reciprocates up and down, and (d) is the three-dimensional diagram of the auxiliary mechanism when it is linked and flipped;

[0069] Figure 10 is Figure 9 Enlarged structure schematic diagram of the A position shown;

[0070] Figure 11 is Figure 9 Schematic diagram of the extraction work of the storage barrel driven by the lifting rod shown;

[0071] Figure 12 is Figure 11 Schematic diagram of the storage barrel rising after extraction is completed shown;

[0072] Figure 13 is Figure 12 Schematic diagram of the storage barrel rising to the material-taking state after extraction is completed shown;

[0073] Figure 14 Detailed structure schematic diagram of the scraping mechanism provided by the present invention;

[0074] Figure 15 Working state schematic diagram of the gas-increasing mechanism provided by the present invention;

[0075] Figure 16 is Figure 15 Schematic diagram of the disassembly of the annular pipe and the bottom plate shown.

[0076] Explanation of the reference numerals in the drawings:

[0077] 1. Base, 2. Heating base, 3. Extraction barrel;

[0078] 4. Extraction mechanism, 41. Storage barrel, 42. Top frame, 43. Middle plate, 44. Rotating seat, 45. Flange seat, 46. Mounting seat, 47. Guide wheel;

[0079] 5. Auxiliary mechanism, 51. Flap, 52. Linking plate, 53. First positioning seat, 54. Linking groove; 55. Second positioning seat, 56. Sleeve, 57. Rotating shaft, 58. Torsion spring, 59. Through hole, 510. Linking wheel,

[0080] 6. Scraping mechanism, 61. Positioning plate, 62. Connecting plate, 63. Scraping ring;

[0081] 7. Gas increasing mechanism, 71. Positioning frame, 72. Extrusion barrel, 73. Bottom plate, 74. Annular pipe, 75. Air outlet pipe, 76. Piston rod, 77. Return spring, 78. First one-way valve, 79. Second one-way valve, 710. Connecting pipe;

[0082] 8. Top plate, 9. Cylinder, 10. Lifting rod, 11. Sealing plate, 12. Lifting plate, 13. Discharge pipe, 14. Corrugated plate.

[0083] The realization, functional features and advantages of the purpose of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0084] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0085] The present invention provides a tantalum-niobium extraction device and a method for preparing a highly selective tantalum-niobium extractant.

[0086] First embodiment:

[0087] Please refer to Figures 1 to 10 , a tantalum-niobium extraction device, including a base 1, an extraction mechanism 4 and an auxiliary mechanism 5;

[0088] A heating base 2 is installed above the base 1, an extraction barrel 3 is installed inside the heating base 2, a top plate 8 is installed at the top of the extraction barrel 3 through bolts, a cylinder 9 is installed at the top of the top plate 8 through bolts, and a vertically liftable lifting rod 10 is installed inside the cylinder 9;

[0089] The extraction mechanism 4 includes a storage barrel 41. The top of the storage barrel 41 is installed with a top frame 42 through bolts. The inner wall of the top frame 42 is fixedly provided with a middle plate 43. The middle position of the top of the middle plate 43 is installed with a rotating seat 44 through bolts. The bottom end of the lifting rod 10 is installed with a flange seat 45 through bolts. The side wall of the top frame 42 is fixedly provided with a mounting seat 46. The inside of the mounting seat 46 is rotatably connected with a guide wheel 47;

[0090] Please refer to Figures 2 to 4 : When working, starting the cylinder 9 can drive the lifting rod 10 to move up and down. Since the lifting rod 10 is installed in the cylinder 9 in a penetrating manner, the upper and lower ends of the lifting rod 10 can be linked to move up and down;

[0091] Before extraction, the user can raise the storage barrel 41 to the upper end of the extraction barrel 3 by raising the lifting rod 10. After that, the user needs to place recycled metal parts (all waste recyclables containing tantalum and niobium, such as waste metal parts and electronic products) inside the storage barrel 41 on both sides of the top plate 8, and then lower the storage barrel 41 into the extraction barrel 3. After that, add extraction agent and solvent into the extraction barrel 3 for wet extraction.

[0092] The auxiliary mechanism 5 includes a flap 51. A through connection groove 54 is opened inside the flap 51. Two first positioning seats 53 are installed at the inner bottom of the extraction barrel 3. The inside of each of the two first positioning seats 53 is fixedly provided with a sleeve 56. Both sides of the flap 51 are fixedly provided with rotating shafts 57. A torsion spring 58 is sleeved on the outer wall of each of the two rotating shafts 57 inside each of the two sleeves 56. Second positioning seats 55 are installed at the inner bottom of the extraction barrel 3 and on both sides of the flap 51. The inside of the second positioning seat 55 is rotatably connected with a linkage plate 52. A through hole 59 is opened inside the linkage plate 52. The side wall of the linkage plate 52 is rotatably connected with a connection wheel 510.

[0093] Please refer to Figure 4 and Figure 5 : It is necessary to lower the storage barrel 41 into the extraction barrel 3, and the bottom surface of the storage barrel 41 needs to be attached to the upper surface of the flap 51. During the extraction process, it is necessary to control the storage barrel 41 to reciprocate up and down inside the extraction barrel 3 to ensure that the solvent can be fully mixed with the raw materials inside the storage barrel 41.

[0094] Please refer to Figure 8 in (a) and (b): In the initial state, the upper surface of the storage barrel 41 and the flap 51 are attached to each other. At this time, the flap 51 and the linkage plate 52 are in the initial flipping state.

[0095] Please refer to Figure 9(c) and (d) in it: when the storage barrel 41 is in the process of reciprocating lifting, the bottom surface of the storage barrel 41 will resist the flap 51 and rotate clockwise along the first positioning seat 53. When the flap 51 moves, it can drive the internal connecting groove 54 to flip and control the internal connecting wheel 510 to slide, affecting the corresponding linkage plate 52 to flip and move counterclockwise along the second positioning seat 55. When the storage barrel 41 is reciprocated and reset upward, the flap 51 will drive the linkage plate 52 to reset to the initial state. The reciprocating flipping movement of the flap 51 and the linkage plate 52 is realized through the linkage of the reciprocating lifting storage barrel 41, so that the raw materials and the solvent are fully mixed, thereby achieving efficient extraction.

[0096] The two rotating shafts 57 are rotatably connected to the axes of the two sleeves 56 through bearings. The two sides of the torsion spring 58 respectively contact the inner wall of the sleeve 56 and the rotating shaft 57. The connecting wheel 510 is slidably connected to the connecting groove 54.

[0097] The flange seat 45 and the rotating seat 44 are rotatably connected, and the bottom surface of the storage bucket 41 and the upper surface of the flap 51 are in contact with each other.

[0098] Understandable: Combined Figure 7 It can be seen that through the setting of the torsion spring 58, when the flap 51 flips on the first positioning seat 53, the flap 51 will drive the rotating shaft 57 to rotate in the sleeve 56. When the rotating shaft 57 rotates, the torsion spring 58 will be controlled to be twisted under force. When the flap 51 loses the force, the torsion spring 58 will reset and drive the flap 51 to return to the state before flipping, thereby achieving automatic flipping and resetting.

[0099] In this embodiment: through the design of the inner and outer storage barrels 41 and the extraction barrel 3, the recycled metal parts (waste metal parts, electronic products and all other waste recycling materials containing tantalum and niobium) are placed in the storage barrel 41, and the extraction solvent is stored in the extraction barrel 3. The raw material and the solvent are mixed by the reciprocating lifting storage barrel 41, and when the storage barrel 41 is in the process of lifting, a flap 51 can be linked to control the four linkage plates 52 to perform clockwise and counterclockwise reciprocating flipping movements, so that the solvent in the extraction barrel 3 can be stirred during the flipping process to ensure that the solvent and the raw material are fully mixed and contacted. Secondly, the linkage plate 52 can realize the formation of a flip vortex along the inner wall of the through hole 59 by flipping the through hole 59 during the flipping process. Therefore, this design realizes efficient mixing and sufficient extraction. At the same time, it can extract in different areas to ensure that the raw material and the extract can be distinguished separately.

[0100] Second embodiment:

[0101] See also Figures 11 to 14, further comprising a scraping mechanism 6, the scraping mechanism 6 includes positioning plates 61 installed on both sides of the lifting rod 10 and above the flange seat 45, a scraping ring 63 is installed at the inner bottom of the storage barrel 41, and connecting plates 62 are fixedly provided on both sides of the inner wall of the scraping ring 63;

[0102] Both of the two positioning plates 61 are slidably connected to the two connecting plates 62 through "T"-shaped blocks.

[0103] Please refer to Figure 11 and Figure 14 : During the working process of the first embodiment, when the lifting rod 10 drives the storage barrel 41 to reciprocate up and down, the positioning plates 61 on both sides of the lifting rod 10 will also move along with the movement of the lifting rod 10. When descending, the positioning plates 61 are controlled to slide inside the connecting plates 62. At this time, the scraping ring 63 is located at the bottommost position of the extraction barrel 3. Therefore, during the working process of the first embodiment, the up and down movement of the storage barrel 41 will not affect the scraping ring 63. The interference effect of the lifting rod 10 on the scraping ring 63 can be eliminated through the sliding connection mode between the positioning plates 61 and the connecting plates 62.

[0104] A corrugated plate 14 is fixedly provided on the inner wall of the storage barrel 41 and in the vertical direction of the guide wheel 47. A discharge pipe 13 is installed at the inner center of the storage barrel 41. Sealing plates 11 are rotatably installed on both sides of the storage barrel 41 and above the top plate 8. Both the upper and lower sides of the corrugated plate 14 are inclined surfaces.

[0105] Please refer to Figure 12 : When the extraction work is completed, the user needs to control the storage barrel 41 to rise through the lifting rod 10. During the rising process, the guide wheel 47 will enter the corrugated plate 14 along the bottom inclined surface of the corrugated plate 14 and rise along with the storage barrel 41. As the storage barrel 41 continues to rise, the guide wheel 47 will follow the trajectory of the corrugated plate 14 to control the top frame 42 and the storage barrel 41 to rotate along the rotating seat 44 and the flange seat 45 to form polarization, so as to vibrate the raw materials in the storage barrel 41;

[0106] And when the lifting rod 10 rises, it will control the positioning plate 61 to drive the connecting plate 62 to control the scraping ring 63 to rise. When the scraping ring 63 rises, it can scrape the extract adhered to the inner wall of the extraction barrel 3 into the interior of the extraction barrel 3.

[0107] Please refer to Figure 13 : As the storage barrel 41 continues to rise, finally the guide wheel 47 and the corrugated plate 14 are separated, the storage barrel 41 returns to the vertical state, and finally the storage barrel 41 rises to the top of the extraction barrel 3. The user can take out the extracted raw materials inside the storage barrel 41 through a manipulator, and after taking them out, new recycled raw materials can be added to continue the subsequent extraction.

[0108] It can be understood that: in combination withFigure 14 It can be seen that the connecting plate 62 does not adopt a through-slot design, so when the lifting rod 10 is lifted or lowered, the stability of the scraper ring 63 can be ensured, and at the same time, when the lifting rod 10 rises, the scraper ring 63 can be driven to rise in conjunction.

[0109] In this embodiment, after the extraction is finished, the storage barrel 41 can be driven to rise in the process of switching from the extraction working state to the initial working state. When the storage barrel 41 rises, the guide wheel 47 can enter the corrugated plate 14 and control the storage barrel 41 to flip and vibrate following the trajectory of the corrugated plate 14. In this way, the residual extract on the raw material inside the storage barrel 41 can be vibrated into the inside of the extraction barrel 3 by flipping and vibrating, thereby ensuring a cleaner and more thorough extraction. Secondly, when the storage barrel 41 rises, it can synchronously drive the scraper ring 63 to rise to scrape off the extract stuck on the inner wall of the extraction barrel 3.

[0110] Secondly, when the raw materials in the storage barrel 41 are placed and moved from the top of the extraction barrel 3 to the bottom, the guide wheel 47 will vibrate the storage barrel 41 through the corrugated plate 14, so that the raw materials inside can be vibrated to ensure uniform distribution and facilitate extraction.

[0111] Third embodiment:

[0112] See also Figure 3 , Figure 6 , Figures 15 to 16 , also includes an air-increasing mechanism 7, which includes a positioning frame 71 installed on one side of the cylinder 9, an extrusion tube 72 is installed inside the positioning frame 71, a piston rod 76 is slidably connected inside the extrusion tube 72, a return spring 77 is sleeved on the outer wall of the piston rod 76, a first one-way valve 78 is installed on the inner bottom of the extrusion tube 72, a second one-way valve 79 is installed on the side of the extrusion tube 72 and on one side of the first one-way valve 78, a connecting pipe 710 is installed at the air outlet end of the second one-way valve 79, two bottom plates 73 are installed on the inner bottom of the storage barrel 41 by bolts, annular tubes 74 are installed inside the two bottom plates 73, four air outlet pipes 75 are installed on the outer wall of the annular tube 74, and a lifting plate 12 is installed on the top of the lifting rod 10 by bolts.

[0113] See also Figure 6 and Figure 15 : During the working process of the first embodiment, the lifting rod 10 is lifted and lowered in a reciprocating manner, so when the lifting rod 10 descends, the lifting plate 12 is driven to descend, and the lifting plate 12 descends to press the piston rod 76 downward in the extrusion cylinder 72. During the downward pressing process, the gas inside the extrusion cylinder 72 can be squeezed through the second one-way valve 79 and then enter the annular tube 74 through the connecting pipe 710, and then the gas is generated through the four outlet pipes 75 to impact the bottom of the storage barrel 41 from bottom to top;

[0114] When the lifting rod 10 is reset during rising, the reset spring 77 acts to push the piston rod 76 to achieve reset. During the reset process, the outside air is inhaled into the extrusion barrel 72 through the first one-way valve 78. Therefore, as the piston rod 76 moves up and down, the extraction barrel 3 can be continuously aerated.

[0115] The upper surface of the lifting plate 12 is in mutual contact with the upper surface of the piston rod 76. The first one-way valve 78 allows one-way passage from outside to inside, and the second one-way valve 79 allows one-way passage from inside to outside.

[0116] The air outlet end of the connecting pipe 710 penetrates through the top plate 8 and the inside of the bottom plate 73 and is hermetically installed with the annular pipe 74. Both the upper and lower ends of the reset spring 77 are in contact with the piston rod 76 and the extrusion barrel 72.

[0117] It can be understood that: from Figure 16 It can be seen that the bottom plate 73 installs the annular pipe 74 in the form of a sandwich. Secondly, the bottom plate 73 can be installed on the inner bottom of the extraction barrel 3 through bolts, so as to realize the stable installation of the annular pipe 74 on the extraction barrel 3.

[0118] In this embodiment: Compared with the traditional design, the design of this case has an aeration mechanism 7. When the lifting rod 10 reciprocates up and down, it can drive the piston rod 76 to move up and down and extrude in the extrusion barrel 72, and the gas in the extrusion barrel 72 can be extruded into the connecting pipe 710, and then the extraction barrel 3 is aerated through the annular pipe 74 and the air outlet pipe 75;

[0119] During the aeration process, the flow rate of the solvent in the extraction barrel 3 can be changed. Compared with the traditional stirring method, the work is stable and the production cost is saved, ensuring sufficient extraction and mixing. Secondly, by increasing the gas content in the solvent, the molecular gap between the solvent and the raw material can be changed, so as to ensure that the extraction solvent can be fully utilized and efficient extraction is realized.

[0120] Fourth Embodiment:

[0121] A method for preparing a highly selective tantalum-niobium extractant

[0122] S1: Synthesis of bisquaternary ammonium salt intermediate

[0123] N,N'-dimethylpiperazine and brominated long-chain alkane (such as 1-bromododecane) are refluxed in ethanol for 12 hours to generate bisquaternary ammonium salt bromide.

[0124] The bromide ion is replaced by nitrate through an ion exchange resin (such as D201 strongly basic anion resin) to obtain a bisquaternary ammonium salt nitrate intermediate.

[0125] CH3-N(CH2CH2N +(CH3)2 + 2C 12 H 25 Br 乙醇,回流 →

[0126] [C 12 H 25 N + CH2CH2N + C 12 H 25 ·2Br + C3H8

[0127] Condition: Ethanol solvent, reflux for 12 hours.

[0128] S2: Phosphonate functionalization modification

[0129] React the intermediate with triethyl phosphite in tetrahydrofuran, control the temperature at 60 - 80 °C, add a catalyst (such as aluminum chloride), to generate a phosphonated bisquaternary ammonium salt precursor.

[0130] Add a long-chain fatty alcohol (such as n-octanol) for transesterification reaction, adjust the pH to neutral to generate a crude product of the target extractant.

[0131] [R1N + CH2CH2N + R2]·2NO 3- + 2PO(OEt)2 →

[0132] AlCl3,60-80℃ [R1N + CH2CH2N + R2]·2NO 3- ·(PO(OEt)2)2

[0133] Condition: Tetrahydrofuran (THF) solvent, catalyzed by aluminum chloride.

[0134] S3: Introduction of long-chain fatty alcohol by transesterification reaction

[0135] Mix the phosphonated bisquaternary ammonium salt precursor with excess n-octanol, add a catalyst PTSA, heat to 80 - 100 °C, stir for 2 - 3 hours, remove the generated short-chain alcohol (such as ethanol) by distillation, cool to room temperature after completion, wash the organic phase with saturated sodium bicarbonate solution to remove the residual catalyst, and then remove the unreacted n-octanol by vacuum distillation.

[0136] [R1N + CH2CH2N + R2]·2NO 3- ·(PO(OEt)2)2 + 2C8H 17 OH →

[0137] pH＝7 [R1N+ CH2CH2N + R2]·2NO 3- ·(PO(OC8H 17 )2)2+2EtOH

[0138] Conditions: neutral pH, excess fatty alcohol, catalyst PTSA, temperature 80 - 100 °C.

[0139] S4: Synthesis of bis - ester quaternary ammonium salt surfactant

[0140] Synthesis of intermediate (Ⅰ)

[0141] Nylon acid (HOOC-(CH2) n -COOH)+ epichlorohydrin (acidic cation resin, 130 °C) → diester intermediate (Cl - OOC-(CH2) n -COO - Cl)

[0142] Conditions: epichlorohydrin as solvent, reaction for 12 hours

[0143] Add adipic acid and excess epichlorohydrin (molar ratio 1:3) to the reaction kettle, then add acidic cation exchange resin (catalyst, dosage is 5% of the total mass), heat to 130 - 140 °C, stir and react for 12 hours. Finally, filter to remove the catalyst, and recover the unreacted epichlorohydrin by vacuum distillation to obtain the white solid intermediate (Ⅰ).

[0144] Synthesis of the final product (Ⅱ)

[0145] Diester intermediate + 2C12H25N(CH3) → Na2CO3, acetone bis - ester quaternary ammonium salt surfactant + 2HCl

[0146] Conditions: acetone as solvent, reflux for 5 hours

[0147] Dissolve intermediate (Ⅰ) in acetone, add excess long - chain alkyl tertiary amine (molar ratio 1:2.2), add sodium carbonate (molar ratio is 2 times that of the intermediate) to neutralize the generated HCl, heat to 60 - 70 °C, stir and react for 5 hours. Filter to remove the generated NaCl, and remove acetone by vacuum distillation. The crude product is recrystallized with n - hexane to obtain the final product bis - ester quaternary ammonium salt surfactant (Ⅱ).

[0148] S5: Synthesis of tertiary amine extractant

[0149] The bis - ester quaternary ammonium salt surfactant is prepared by the esterification reaction of dibasic acid and epichlorohydrin to form an intermediate, and then the quaternization reaction with long - chain alkyl tertiary amine. This surfactant has a bis - ester structure, enhancing its hydrophobicity and interfacial activity.

[0150] C8H17 Br + α-methylbenzylamine KOH,乙醇 C8H 17 N(CH2C6H5)CH3 + KBr

[0151] Condition: Base catalysis, heating under reflux

[0152] Add α-methylbenzylamine and 1-bromooctane (molar ratio 1:1.2) into a three-necked flask. Add ethanol as the solvent, and add KOH (molar ratio 1.5 times that of the alkyl bromide). Heat to reflux of ethanol (80 - 90 °C), stir and react for 8 - 10 hours. After the reaction is completed, cool to room temperature, filter to remove the KBr precipitate. Remove ethanol by vacuum distillation, and purify the crude product by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 10:1). Collect the target component to obtain a colorless liquid tertiary amine extractant.

[0153] S6: Purification and modification

[0154] Remove unreacted fatty alcohol and by-products by silica gel column chromatography, and collect the target component.

[0155] The specific steps are to dissolve the crude reaction product in a small amount of dichloromethane, separate the target product by silica gel column chromatography, the eluent is dichloromethane and methanol, collect the target component, and remove the solvent by vacuum distillation.

[0156] Add an antioxidant (such as 2,6-di-tert-butyl-p-cresol) to improve the chemical stability of the extractant.

[0157] The specific operation steps are to add 0.1% - 0.5% of an antioxidant (such as BHT) to the purified extractant and stir until completely dissolved to ensure the chemical stability of the extractant.

[0158] This example: This highly selective tantalum and niobium extractant is mainly used for recycled waste metal parts. In traditional tantalum and niobium separation processes, solvent extraction is mostly used, but existing extractants (such as MIBK, TBP, etc.) have problems such as low selectivity, easy emulsification, and the need for a high-acidity environment. In recent years, bisquaternary ammonium salt extractants have attracted attention due to their high coordination ability, but their separation efficiency for tantalum and niobium still needs to be improved. In addition, in traditional processes, the extractant is easily oxidized and inactivated, and the co-extraction phenomenon of impurity metals (such as iron, titanium) is significant, resulting in high subsequent purification costs;

[0159] Core skeleton: Bisquaternary ammonium salt structure (such as N,N'-dimethylpiperazine bisquaternary ammonium salt), linked by a straight-chain or cyclic aliphatic chain segment (C8 - C12) to enhance the miscibility with organic solvents.

[0160] Functional groups: Phosphonate groups (—PO(OR3)2) are introduced at both ends of the quaternary ammonium salt to enhance the complexing ability for high-valent metal ions; long-chain fatty alcohols (such as n-octanol and isodecyl alcohol) are modified on the side chains to inhibit the co-extraction of impurity metals through steric hindrance effects.

[0161] Example of molecular formula:

[0162] [R1N+CH2CH2N + R2]·2X - ·(PO(OR3)2)2

[0163]

[0164] Wherein R1, R2 are methyl or ethyl, and R3 is C8-C12 alkyl.

[0165] Please refer to Figures 1 to 16 The working principle of the tantalum-niobium extraction device provided by the present invention is as follows:

[0166] Step S1, before extraction, the user can raise the storage bucket 41 to the upper end of the extraction bucket 3 by raising the lifting rod 10, and then place the recycled metal parts (waste metal parts, electronic products and other waste recycling containing tantalum and niobium) inside the storage bucket 41 on both sides of the top plate 8, and then lower the storage bucket 41 into the extraction bucket 3;

[0167] Step S2, when the storage barrel 41 is in the process of reciprocating lifting, the bottom surface of the storage barrel 41 will resist the flap 51 and rotate clockwise along the first positioning seat 53. When the flap 51 moves, it can drive the internal connection groove 54 to flip and control the internal connection wheel 510 to slide and affect the corresponding linkage plate 52 to flip and move counterclockwise along the second positioning seat 55. When the storage barrel 41 is reciprocating and reset upward, the flap 51 will drive the linkage plate 52 to reset to the initial state. The reciprocating flipping movement of the flap 51 and the linkage plate 52 is realized through the linkage of the reciprocating lifting storage barrel 41 to achieve full mixing of the raw materials and the solvent, and achieve efficient extraction;

[0168] Step S3, when the extraction work is completed, the user needs to control the storage barrel 41 to rise through the lifting rod 10. During the rising process, the guide wheel 47 will follow the storage barrel 41 along the bottom slope of the corrugated plate 14 and enter the corrugated plate 14. As the storage barrel 41 continues to rise, the guide wheel 47 will follow the trajectory of the corrugated plate 14 to control the top frame 42 and the storage barrel 41 to rotate along the rotating seat 44 and the flange seat 45 to form polarization, thereby vibrating the raw materials in the storage barrel 41. Finally, the user needs to open the discharge pipe 13 to discharge all the extracts.

[0169] The above are only the preferred embodiments of the present invention, and do not thereby limit the patent scope of the present invention. Any equivalent structural transformation made under the concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields, is included within the patent protection scope of the present invention.

Claims

1. A tantalum-niobium extraction device, characterized in that It includes a base, an extraction mechanism and an auxiliary mechanism; A heating base is installed above the base, an extraction barrel is installed inside the heating base, a top plate is installed at the top of the extraction barrel through bolts, a cylinder is installed at the top of the top plate through bolts, and a vertically liftable lifting rod is installed inside the cylinder; The extraction mechanism includes a storage barrel, a top frame is installed at the top of the storage barrel through bolts, a middle plate is fixedly arranged on the inner wall of the top frame, a rotating seat is installed at the middle position of the top of the middle plate through bolts, a flange seat is installed at the bottom end of the lifting rod through bolts, a mounting seat is fixedly arranged on the side wall of the top frame, and a guide wheel is rotatably connected inside the mounting seat; The auxiliary mechanism includes a flap, a through connection groove is opened inside the flap, two first positioning seats are installed at the inner bottom of the extraction barrel, sleeves are fixedly arranged inside both of the two first positioning seats, shafts are fixedly arranged on both sides of the flap, torsion springs are sleeved on the outer walls of the two shafts and inside the two sleeves, second positioning seats are installed at the inner bottom of the extraction barrel and on both sides of the flap, a linkage plate is rotatably connected inside the second positioning seat, a through hole is opened inside the linkage plate, and a connection wheel is rotatably connected to the side wall of the linkage plate.

2. The tantalum-niobium extraction device according to claim 1, wherein Both of the two shafts are rotatably connected to the axis of the two sleeves through bearings, both sides of the torsion spring are respectively in contact with the inner wall of the sleeve and the shaft, and the connection wheel is slidably connected with the connection groove.

3. The tantalum-niobium extraction device according to claim 1, characterized in that, The flange seat and the rotating seat are rotatably connected, and the bottom surface of the storage barrel is in contact with the upper surface of the flap.

4. The tantalum-niobium extraction device according to claim 1, wherein It further includes a scraping mechanism, the scraping mechanism includes positioning plates installed on both sides of the lifting rod and above the flange seat, a scraping ring is installed at the inner bottom of the storage barrel, and connecting plates are fixedly arranged on both sides of the inner wall of the scraping ring; Both of the two positioning plates are slidably connected with the two connecting plates through "T"-shaped blocks.

5. The tantalum-niobium extraction device according to claim 1, characterized in that, A corrugated plate is fixedly arranged on the inner wall of the storage barrel and in the vertical direction of the guide wheel, a discharge pipe is installed at the central axis of the storage barrel, sealing plates are rotatably installed above the storage barrel and on both sides of the top plate, and both the upper and lower sides of the corrugated plate are of inclined surface structures.

6. The tantalum-niobium extraction device according to claim 1, wherein It further includes an air-increasing mechanism, the air-increasing mechanism includes a positioning frame installed on one side of the cylinder, an extrusion barrel is installed inside the positioning frame, a piston rod is slidably connected inside the extrusion barrel, a return spring is sleeved on the outer wall of the piston rod, a first one-way valve is installed at the inner bottom of the extrusion barrel, a second one-way valve is installed on the side of the extrusion barrel and on one side of the first one-way valve, a connecting pipe is installed at the air outlet end of the second one-way valve, two bottom plates are installed at the inner bottom of the storage barrel through bolts, a ring pipe is installed inside both of the two bottom plates, four air outlet pipes are installed on the outer wall of the ring pipe, and a lifting plate is installed at the top end of the lifting rod through bolts.

7. The tantalum-niobium extraction device according to claim 6, characterized in that, The upper surface of the lifting plate is in contact with the upper surface of the piston rod, the first one-way valve allows one-way passage from outside to inside, and the second one-way valve allows one-way passage from inside to outside.

8. The tantalum-niobium extraction device according to claim 6, characterized in that, The outlet end of the connecting pipe penetrates through the inside of the top plate and the bottom plate and is sealed and installed with the annular pipe. The upper and lower ends of the return spring are in contact with the piston rod and the extrusion cylinder respectively.

9. A preparation method of a high-selectivity tantalum and niobium extractant, characterized in that, The method for preparing the highly selective tantalum-niobium extractant is used for the tantalum-niobium extraction device as described in any one of claims 1-8, and includes the following steps: S1: Synthesis of bisquaternary ammonium salt intermediate React N,N'-dimethylpiperazine with brominated long-chain alkane (such as 1-bromododecane) in ethanol by refluxing for 12 hours to form bisquaternary ammonium salt bromide. Replace bromide ions with nitrate ions through ion exchange resin (such as D201 strong basic anion resin) to obtain bisquaternary ammonium salt nitrate intermediate. CH3-N(CH2CH2N + CH3)2+2C 12 H 25 Br 乙醇,回流 →[C 12 H 25 N + CH2CH2N + C 12 H 25 ·2Br + C3H8 Condition: Ethanol solvent, reflux for 12 hours. S2: Phosphonate functionalization React the intermediate with triethyl phosphite in tetrahydrofuran, control the temperature at 60-80 °C, add a catalyst (such as aluminum chloride), and generate a phosphonated bisquaternary ammonium salt precursor. Add long-chain fatty alcohol (such as n-octanol) for transesterification reaction, adjust the pH to neutral, and generate the crude target extractant. [R1N + CH2CH2N + R2]·2NO 3- +2PO(OEt)2 → AlCl3,60-80℃ [R1N+CH2CH2N+R2]·2NO 3- ·(PO(OEt)2)2 Condition: Tetrahydrofuran (THF) solvent, catalyzed by aluminum chloride. S3: Introduction of long-chain fatty alcohol by transesterification reaction Mix the phosphonated bisquaternary ammonium salt precursor with excessive n-octanol, add catalyst PTSA, heat to 80-100 °C, stir for 2-3 hours, remove the generated short-chain alcohol (such as ethanol) by distillation, cool to room temperature after completion, wash the organic phase with saturated sodium bicarbonate solution to remove the residual catalyst, and then remove the unreacted n-octanol by vacuum distillation. [R1N + CH2CH2N + R2]·2NO 3- ·(PO(OEt)2)2 + 2C8H 17 OH → pH＝7 [R1N + CH2CH2N + R2]·2NO 3- ·(PO(OC8H 17 )2)2 + 2EtOH Condition: Neutral pH, excessive fatty alcohol, catalyst PTSA, temperature 80-100 °C. S4: Synthesis of bis-ester quaternary ammonium salt surfactant Synthesis of intermediate (Ⅰ) Nylon acid (HOOC-(CH2) n -COOH) + Epichlorohydrin (acidic cation resin, 130 °C) → Diester intermediate (Cl-OOC-(CH2) n -COO-Cl) Condition: Epichlorohydrin as solvent, react for 12 hours Add adipic acid and excessive epichlorohydrin (molar ratio 1:3) to the reaction kettle, then add acidic cation exchange resin (catalyst, dosage is 5% of the total mass), heat to 130-140 °C, stir and react for 12 hours, finally filter to remove the catalyst, and recover the unreacted epichlorohydrin by vacuum distillation to obtain a white solid intermediate (Ⅰ). Synthesis of end product (Ⅱ) Diacid ester intermediate + 2C12 H25 N(CH3)2 → Na2 CO3, acetone bis-ester quaternary ammonium salt surfactant + 2HCl Condition: Acetone solvent, reflux for 5 hours Dissolve intermediate (Ⅰ) in acetone, add excessive long-chain alkyl tertiary amine (molar ratio 1:2.2), add sodium carbonate (molar ratio is 2 times that of the intermediate) to neutralize the generated HCl, heat to 60-70 °C, stir and react for 5 hours. Filter to remove the generated NaCl, and remove acetone by vacuum distillation. The crude product is recrystallized with n-hexane to obtain the end product bis-ester quaternary ammonium salt surfactant (Ⅱ). S5: Synthesis of tertiary amine extractant The bis-ester quaternary ammonium salt surfactant is prepared by esterification reaction of dibasic acid and epichlorohydrin to form an intermediate, and then quaternization reaction with long-chain alkyl tertiary amine. This surfactant has a bis-ester structure, enhancing its hydrophobicity and interfacial activity. C8H 17 Br + α-methylbenzylamine KOH,乙醇 C8H 17 N(CH2C6H5)CH3 + KBr Condition: Catalyzed by base, heat and reflux Add α-methylbenzylamine and 1-bromooctane (molar ratio 1:1.2) into a three-necked flask. Add ethanol as the solvent and add KOH (molar ratio 1.5 times that of alkyl bromide). Heat to ethanol reflux (80 - 90 °C) and stir the reaction for 8 - 10 hours. After the reaction is completed, cool to room temperature and filter to remove the KBr precipitate. Remove ethanol by vacuum distillation and purify the crude product by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 10:1). Collect the target component to obtain a colorless liquid tertiary amine extractant. S6: Purification and modification Remove unreacted fatty alcohol and by-products by silica gel column chromatography and collect the target component. The specific steps are to dissolve the crude reaction product in a small amount of dichloromethane, separate the target product by silica gel column chromatography, the eluent is dichloromethane and methanol, collect the target component, and remove the solvent by vacuum distillation. Add antioxidants (such as 2,6-di-tert-butyl-p-cresol) to improve the chemical stability of the extractant. The specific operation steps are to add 0.1% - 0.5% of antioxidant (such as BHT) to the purified extractant and stir until completely dissolved to ensure the chemical stability of the extractant.

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