Method for the enhanced extraction and separation of lutetium and ytterbium

Abstract

The present application relates to the technical field of rare earth element separation extraction, and discloses a method for enhancing extraction separation of lutetium and ytterbium, comprising the following steps: step 1, dissolving a sample to be separated containing a lutetium compound and a ytterbium compound, and a carboxylic complexing agent in water as an aqueous phase; step 2, dissolving an organic phosphorus extractant in a diluent as an organic phase; mixing the organic phase and the aqueous phase to perform extraction, and obtaining an organic phase containing lutetium and ytterbium elements; and step 3, adding a carboxylic complexing agent to the organic phase obtained in step 2 to perform back extraction, so as to realize separation of lutetium and ytterbium. In the present application, an organic phosphoric acid ester extractant is used as a normal sequence ligand, and a carboxylic complexing agent is used as a reverse sequence ligand, so that the lutetium and ytterbium are separated by the synergistic effect of the normal and reverse sequence ligands, the lutetium and ytterbium separation factor is effectively improved, the lutetium and ytterbium separation and purification process is effectively shortened, and the separation efficiency and equipment investment are improved.

Description

Technical Field

[0001] This invention relates to the field of rare earth element separation and extraction technology, specifically to a method for enhanced extraction and separation of lutetium and ytterbium. Background Technology

[0002] Rare earth elements are a group of metallic elements with similar physicochemical properties, including 15 lanthanide elements from lanthanum (La) to lutetium (Lu), and two elements: scandium (Sc) and yttrium (Y). Ytterbium (Yb) and lutetium are the last two elements in the lanthanide series and belong to the heavy rare earth elements. Ytterbium can form both +2 and +3 oxidation states, but the +3 oxidation state is more stable, while lutetium only forms the +3 oxidation state. Ytterbium and lutetium possess excellent magnetic, fluorescent, and catalytic properties, making them important in modern industrial and technological fields such as electronics, new energy, aerospace, catalysts, and medicine.

[0003] Ytterbium is primarily used as a shielding coating material and a magnetostrictive material. It can also be used in the manufacture of lasers, high-strength alloys, and fiber optic amplifiers. Some of its compounds can be used as catalysts in organic synthesis and homogeneous catalytic reactions. Lutetium can be used as a catalyst in petrochemicals, a raw material for magnetic bubble storage devices, and a raw material for special alloys. Its isotopes... 177 Luteinium (L) possesses integrated diagnostic and therapeutic capabilities and unique radiochemical properties, playing a vital role in the field of nuclear medicine. Because ytterbium and lutetium belong to the same lanthanide series and are adjacent in position, with trivalent ionic radii of 85.8 pm and 84.8 pm respectively, their chemical properties are very similar, posing a significant challenge to their separation and purification.

[0004] Common methods for rare earth separation include fractional crystallization, fractional precipitation, redox methods, solvent extraction, and ion exchange. Among these, solvent extraction offers advantages such as good separation efficiency, large production capacity, strong process controllability, and ease of large-scale continuous production, making it the most widely used and technologically mature method for rare earth element separation. Currently, research and development of extractants for heavy rare earth separation mainly focuses on phosphorus (phosphine) extractants with low pKa values ​​and high chain barriers, which are highly favored in industrial applications due to their excellent extraction and separation performance among heavy rare earth elements.

[0005] Acidic phosphorus (phosphine) extractants such as di(2-ethylhexyl)phosphoric acid (P204), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (P507), and bis(2,4,4-trimethylpentyl)phosphonic acid (Cyanex 272) are widely used in the separation of heavy rare earth elements. However, there are still many problems in the application of Lu / Yb separation. For example, P204 has a low separation factor for Lu / Yb and is difficult to back-extract; although P507 has a relatively high separation factor for Lu / Yb (SF = 1.6-1.8), it has the defects of high back-extraction acidity and incomplete back-extraction; Cyanex 272 has a lower back-extraction acidity, but the separation factor for Lu / Yb is still not high enough, only 1.31, and the viscosity of the organic phase increases when extracting rare earth elements, resulting in a decrease in extraction efficiency. Some new extractants, such as bis(2-ethylhexyl)phosphonic acid (P227) and bis(2,3-dimethylbutyl)phosphonic acid (HYY-2), have slightly higher separation factors than Cyanex272. However, P227 has slow extraction kinetics and is more difficult to synthesize, while HYY-2 has higher solubility in the aqueous phase due to its shorter carbon chain.

[0006] Chinese patent document CN100352954A reports a process for separating rare earth elements using an extraction system with added modifiers. It utilizes P507 + methylheptanol to improve the selectivity and back-extraction ability for some rare earth elements, but does not improve the separation factor for Lu / Yb.

[0007] Another published patent (CN102618736A) reports a method for extracting rare earth elements using 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester trialkylmethylammonium ([A336][P507]) and phosphonic acid di(2-ethylhexyl) ester trialkylmethylammonium ([A336][P204]). In this process, cations and anions exhibit synergistic and competitive effects, which improves the separation efficiency of rare earth elements. It also has the advantages of low acidity required for extraction and back-extraction, and low acid consumption. However, the separation factor of this system for Lu / Yb is limited. The separation factor of [A336][P204] for Lu / Yb in mixed rare earth solutions is only 1.85. Summary of the Invention

[0008] This invention addresses the problems of low separation factor, insufficient product purity, long process flow, and large consumption of chemical raw materials in the Lu / Yb extraction and separation process. It provides a method for enhancing the extraction and separation of lutetium and ytterbium. This method uses organophosphate extractants as forward ligands and carboxylic acid complexing agents as reverse ligands. The synergistic effect of forward and reverse ligands enhances the separation of lutetium and ytterbium, effectively improving the lutetium-ytterbium separation factor.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A method for enhancing the extraction and separation of lutetium and ytterbium includes the following steps:

[0011] Step 1: Dissolve the sample to be separated, containing lutetium compounds and ytterbium compounds, and a carboxylic acid complexing agent in water to form the aqueous phase;

[0012] Step 2: Dissolve the organophosphorus extractant in a diluent to form the organic phase; mix the organic phase and the aqueous phase for extraction to obtain an organic phase containing lutetium and ytterbium.

[0013] Step 3: Add a carboxylic acid complexing agent to the organic phase obtained from step 2 for back-extraction to achieve the separation of lutetium and ytterbium.

[0014] The carboxylic acid complexing agents include one or more of ethylenediaminetetraacetic acid (EDTA), acetic acid, lactic acid, diethylenetriaminepentaacetic acid (DTPA), 1,3-diamino-2-propanol-N,N,N',N'-tetraacetic acid, and bis(2-aminoethyl) ether N,N,N',N'-tetraacetic acid (OBETA).

[0015] Preferably, the carboxylic acid complexing agent is one or more of DTPA, 1,3-diamino-2-propanol-N,N,N',N'-tetraacetic acid, and OBETA. DTPA is further preferred as the complexing agent.

[0016] The organophosphorus extractant includes one or more of the following: tributyl phosphate (TBP), trioctylphosphine oxide (TOPO), di(2-ethylhexyl)phosphine (P204), mono-2-ethylhexyl phosphonate (P507), bis(2,4,4-trimethylpentyl)phosphonic acid (Cyanex 272), di(2-ethylhexyl)phosphonic acid (P227), and dimethylheptyl methylphosphonate (P350). Preferably, the organophosphorus extractant is any one or more of P507, P350, P227, and C272.

[0017] The diluent includes one of kerosene, heptane, and dodecane.

[0018] The lutetium compound includes one or more of lutetium nitrate, chloride, and sulfate; the ytterbium compound includes one or more of ytterbium nitrate, chloride, and sulfate.

[0019] In step 2, the extraction temperature is at room temperature, and the extraction time is at least 10 minutes. The preferred extraction time is 10-30 minutes. The separation effect is not ideal when the extraction time is less than 10 minutes, and the extraction equilibrium is basically maintained after 30 minutes.

[0020] The molar concentration of organophosphorus extractant in the organic phase of step 2 is 3-30 mmol / L.

[0021] In step 1, the molar concentration of the carboxylic acid complexing agent in the aqueous phase is 1-50 mmol / L. Preferably, the molar concentration is 1-10 mmol / L, such as 1 mmol / L, 3 mmol / L, or 5 mmol / L.

[0022] In step 1, the pH of the aqueous phase is 1-3; preferably, the pH of the aqueous phase is 1.5-2.5; in step 2, the volume ratio of the organic phase to the aqueous phase is 1:10-10:1, preferably 1:2-2:1.

[0023] During back-extraction in step 3, the molar concentration of carboxylic acid complexes in the organic phase is 1-50 mmol / L, preferably 10-30 mmol / L.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) In this invention, organophosphate extractants are used as forward ligands and carboxylic acid complexing agents are used as reverse ligands. The separation of lutetium and ytterbium is enhanced through the synergistic effect of forward and reverse ligands, which effectively improves the lutetium and ytterbium separation factor. The separation and purification process of lutetium and ytterbium is effectively shortened, and the separation efficiency and equipment investment are improved.

[0026] (2) The reverse ligand carboxylic acid complexing agent in this invention can be used as both a detergent and a back-extraction agent, which reduces the acid and alkali consumption in the lutetium-ytterbium separation process and has the advantages of being economical, environmentally friendly and highly efficient. Attached Figure Description

[0027] Figure 1 The effect of P350 concentration on Lu / Yb separation efficiency in Example 1.

[0028] Figure 2 The effect of C272 concentration on Lu / Yb separation efficiency in Example 2.

[0029] Figure 3 The effect of P227 concentration on Lu / Yb separation efficiency in Example 3.

[0030] Figure 4 The effect of DTPA concentration on Lu / Yb separation efficiency in Example 4.

[0031] Figure 5 This illustrates the effect of extraction time on the Lu / Yb separation effect in Example 5.

[0032] Figure 6 This illustrates the effect of the initial pH of the aqueous phase on the Lu / Yb separation effect in Example 6.

[0033] Figure 7 The effect of the concentration of the back-extraction agent DTPA on the Lu / Yb back-extraction effect in Example 7. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should all be covered within the protection scope of this invention.

[0035] All raw materials used in the following specific embodiments were purchased commercially. Extraction partition ratio D, separation factor SF of lutetium and ytterbium. Lu / Yb The formulas for calculating the extraction rate E and the back-extraction rate S are as follows:

[0036]

[0037] Among them, [M] aq,ini [M] represents the initial concentration of rare earth ions in the aqueous phase before extraction. aq,eq [M] represents the equilibrium concentration of rare earth ions in the aqueous phase after extraction. s D represents the equilibrium concentration of rare earth ions in the aqueous phase after back-extraction. Lu The extraction partition ratio of lutetium, D Yb The extraction distribution ratio of ytterbium.

[0038] Example 1

[0039] Using P350 as the extractant, the effect of P350 concentration on extraction and separation was investigated. At the same time, the separation effect of Lu / Yb when a certain amount of DTPA was added was compared to determine the optimal P350 concentration and the effect of DTPA on the Lu / Yb separation factor.

[0040] Step 1: Weigh lutetium nitrate and ytterbium nitrate to prepare a solution containing Lu. 3+ and Yb 3+ Each 0.5 mmol / L solution was prepared. DTPA carboxylic acid extractant was added to some samples to make the concentration 10 mmol / L, while no DTPA was added to others. The pH of the solution was adjusted to 2 with nitric acid to obtain the aqueous phase to be extracted.

[0041] Step 2: Dissolve the extractant P350, an organophosphorus extractant, in the diluent dodecane to obtain concentrations of 3 mmol / L, 4.5 mmol / L, 6 mmol / L, 7.5 mmol / L, 9 mmol / L, 18 mmol / L, 27 mmol / L, and 30 mmol / L, respectively, to obtain the organic phase.

[0042] Step 3: Mix the organic and aqueous phases in equal proportions, and shake at 300 rpm for 30 minutes at room temperature in a shaker. Then, centrifuge at 3000 rpm for 2 minutes to separate the phases. Measure the Lu in the aqueous phases before and after extraction using ICP-OES. 3+ and Yb 3+ Concentration, and the distribution ratio (D) and separation factor (SF) are calculated using the following formulas (1)(2)(3). Lu / Yb ) and extraction rate (E).

[0043] The results are as follows Figure 1 As shown, the extraction rates of Lu and Yb significantly increased with increasing P350 concentration. Specifically, without DTPA, P350 significantly improved the extraction rates of Lu. 3+ and Yb 3+ The extraction capacity is strong. When the P350 concentration increased from 3 mmol / L to 7.5 mmol / L, the extraction rates of Lu and Yb increased from 48.3% and 34.1% to 94.9% and 91.1%, respectively. Almost complete extraction of Yb and Lu was achieved using 9 mmol / L of P350. During this process, changes in P350 concentration had no significant effect on the Lu / Yb separation factor. Lu / Yb It remained stable between 1.80 and 1.82.

[0044] When DTPA is added to the aqueous phase, P350 affects Lu 3+ and Yb 3+ The extraction efficiency was significantly reduced; 9 mmol / L P350 significantly reduced the extraction efficiency of Lu 3 + and Yb 3+ The extraction rates were only 48.7% and 27.7%, respectively, mainly due to the competitive relationship between the complexation of the reverse ligand DTPA on Lu and Yb and the extractant. Since P350 preferentially extracts Lu, while DTPA preferentially complexes Yb, a "push-pull" synergistic extraction effect is achieved, effectively improving the separation of Lu / Yb, as shown in Table 1. Lu / Yb The value increased from around 1.81 to around 2.52, which is much higher than most reported extraction systems.

[0045] Table 1. Separation factors of Lu / Yb when P350 is used as the extractant.

[0046] [P350](mmol / L) <![CDATA[SF without DTPA Lu / Yb > <![CDATA[SF of 10 mM DTPA Lu / Yb > 3 1.81 2.33 4.5 1.81 2.71 6 1.82 2.65 7.5 1.82 2.52 9 1.80 2.49 18 - 2.50 27 - 2.47 30 - 2.52

[0047] Example 2

[0048] Extraction experiments were conducted according to the method in Example 1, using C272 as the extractant. The effect of its concentration on extraction and separation was investigated, and the extraction results after adding 1 mM DTPA were compared.

[0049] like Figure 2 As shown, the extraction rates of Lu and Yb significantly increased with increasing C272 concentration. Specifically, without DTPA, the extraction rate showed a more significant change with C272 concentration; when the C272 concentration was 30 mmol / L, the extraction rates of both Lu and Yb reached over 80%. During this process, changes in C272 concentration had no significant effect on the Lu / Yb separation factor. Lu / Yb The concentration remained stable between 1.57 and 1.61. When DTPA was added to the aqueous phase, the extraction rates of Lu and Yb decreased significantly, showing a linear relationship with the concentration of C272. Similar to the results of Example 1, the introduction of DTPA also increased the Lu / Yb separation factor, as shown in Table 2. Lu / Yb It has increased to around 2.23.

[0050] Table 2 shows the separation factors of Lu / Yb when C272 is used as the extractant and 1 mM DTPA is used as the complexing agent.

[0051] [C272](mmol / L) <![CDATA[SF without DTPA Lu / Yb > <![CDATA[SF of 1 mM DTPA Lu / Yb > 6 1.57 1.88 9 1.58 1.82 12 1.59 2.23 15 1.60 2.16 18 1.60 2.23 24 1.61 2.33 30 1.61 2.22 36 - 2.16 42 - 2.21 48 - 2.25

[0052] Example 3

[0053] Extraction experiments were conducted according to the method in Example 1, using P227 as the extractant. The effect of its concentration on extraction and separation was investigated, and the extraction results after adding 1 mM DTPA were compared.

[0054] like Figure 3 As shown, the extraction rates of both Lu and Yb significantly increased with increasing P227 concentration. Specifically, without DTPA, the extraction rate showed a more significant change with P227 concentration; when the P227 concentration was 30 mmol / L, the extraction rates of both Lu and Yb reached over 97%. During this process, changes in P227 concentration had no significant effect on the Lu / Yb separation factor; however, with increasing P227 concentration, the extraction rate of SF... Lu / Yb The extraction efficiency increased slightly, from 1.62 to 1.73; when DTPA was added to the aqueous phase, the extraction rates of Lu and Yb decreased significantly, showing a linear relationship with the concentration of P227. Similar to the results of Examples 1 and 2, the introduction of DTPA increased the Lu / Yb separation factor, as shown in Table 3. Lu / Yb It has increased to around 2.40.

[0055] Table 3 shows the separation factors of Lu / Yb when P227 is used as the extractant and 1 mM DTPA is used as the complexing agent.

[0056] [P227](mmol / L) <![CDATA[SF without DTPA Lu / Yb > <![CDATA[SF of 1 mM DTPA Lu / Yb > 6 1.62 2.18 9 1.66 2.23 12 1.68 2.29 15 1.70 2.33 18 1.72 2.35 24 1.73 2.39 30 1.73 2.39 36 - 2.40 42 - 2.42 48 - 2.43

[0057] Examples 1-3 all involve enhanced extraction and separation systems formed by organophosphorus extractants and carboxylic acid complexing agents (DTPA). Since organophosphorus extractants themselves have varying extraction and separation capabilities for Lu and Yb, the resulting extraction systems also differ. A comparison of extraction rates and separation factors yields the following results: P350 > P227 > C272.

[0058] Example 4

[0059] The effect of the concentration of the carboxylic acid complexing agent DTPA on the extraction and separation efficiency of Lu / Yb was investigated. The method of Example 1 was followed, wherein the concentration of extractant P350 in the organic phase was 9 mmol / L, the concentration of DTPA in the aqueous phase was adjusted to 0.1-10 mmol / L, and other conditions remained consistent.

[0060] like Figure 4 As shown, this extraction system is effective for Lu 3+ / Yb 3+ The extraction rate was negatively correlated with the concentration of DTPA. Furthermore, the separation coefficient of Lu / Yb increased with increasing DTPA concentration, as shown in Table 4. When the DTPA concentration increased from 0 to 1 mmol / L, the SF... Lu / Yb The concentration increased from 1.81 to 2.58; while when the DTPA concentration reached 1–10 mmol / L, SF… Lu / Yb The situation remains basically stable and unchanged.

[0061] Table 4 Extraction rates and separation factors of Lu / Yb at different DTPA concentrations

[0062]

[0063]

[0064] Example 5

[0065] Extraction time was determined according to the method described in Example 1, wherein the concentration of extractant P350 in the organic phase was 9 mmol / L and the concentration of DTPA in the aqueous phase was 1 mmol / L. The effect of different oscillation times on Lu at an oscillation rate of 300 rpm was investigated. 3+ / Yb 3+ The impact of extraction efficiency.

[0066] like Figure 5 As shown in Table 5, when the oscillation time is <10 min, the system's effect on Lu 3+ / Yb 3+ The extraction rate and separation factor both continuously increased. When the time was extended from 10 min to 30 min, Lu 3+ / Yb 3+ The extraction rate did not change significantly, while the separation factor increased from 2.27 to 2.55.

[0067] Table 5 Extraction rates and separation factors of Lu / Yb at different extraction times

[0068] Extraction time (min) <![CDATA[E Lu (%)]]> <![CDATA[E Yb (%)]]> <![CDATA[SF Lu / Yb ]]> 1 18.89 14.63 1.36 3 35.73 26.80 1.52 5 52.53 40.37 1.64 10 78.40 61.52 2.27 15 79.70 62.14 2.39 20 80.08 62.41 2.42 25 82.37 64.96 2.52 30 83.14 65.98 2.55

[0069] Example 6

[0070] The effect of initial pH of the aqueous phase on the extraction and separation effect of Lu / Yb was studied. The extraction experiment was carried out according to the method in Example 1, wherein the concentration of extractant P350 in the organic phase was 9 mmol / L and the concentration of DTPA in the aqueous phase was 1 mmol / L. The initial pH of the aqueous phase was adjusted to 1, 1.5, 2, 2.5, 3, 4 and 5 respectively.

[0071] like Figure 6 And as shown in Table 6, when pH = 1, SF Lu / Yb =1.75, at this point DTPA is effective against Lu 3+ / Yb 3+ The complexation effect was almost completely inhibited, and Lu / Yb separation was achieved solely through the extraction action of P350; when pH ≥ 3, DTPA significantly reduced the concentration of Lu / Yb. 3+ / Yb 3+ The complexation effect was too strong, resulting in a significant decrease in extraction rate and making Lu / Yb separation impossible; when pH=2, SF Lu / Yb At its peak, the extraction effect of P350 and the complexation effect of DTPA synergistically enhance the separation of Lu / Yb.

[0072] Table 6 Extraction rates and separation factors of Lu / Yb at different initial pH values ​​in aqueous phases.

[0073] pH <![CDATA[E Lu (%)]]> <![CDATA[E Yb (%)]]> <![CDATA[SF Lu / Yb ]]> 1 22.09 14.08 1.75 1.5 76.89 62.87 1.97 2 82.27 64.84 2.52 2.5 65.10 48.03 2.02 3 30.44 23.41 1.44 4 2.32 1.16 - 5 0 0 -

[0074] Example 7

[0075] Using DTPA as a back-extraction agent, Lu in the supported organic phase obtained at pH=2 in Example 6 was analyzed. 3+ / Yb 3+ Perform back-extraction experiments. Prepare DTPA solutions with a concentration of 1-10 mmol / L and adjust their pH to 2 with nitric acid. Mix the loaded organic phase and DTPA solution in equal proportions and perform back-extraction experiments according to the method in Example 1.

[0076] Table 7. Extraction rates and separation factors of Lu / Yb at different DTPA concentrations.

[0077] [DTPA](mmol / L) <![CDATA[S Lu (%)]]> <![CDATA[S Yb (%)]]> <![CDATA[SF Lu / Yb ]]> 1 19.01 34.22 2.22 2 31.50 52.51 2.41 4 40.44 63.69 2.59 6 44.34 68.05 2.68 8 46.74 70.49 2.73 10 48.40 71.24 2.65

[0078] like Figure 7 And as shown in Table 7, when Lu is back-extracted using DTPA 3+ and Yb3+ The back-extraction rate is not high; when the DTPA concentration reaches 10 mmol / L, Lu 3+ and Yb 3+ The highest back-extraction rates were 71% and 48%, respectively. However, a high Yb / Lu separation efficiency was maintained during the back-extraction process. When the DTPA concentration was ≥4 mmol / L, SF... Yb / Lu ≥2.59. This indicates that DTPA can replace inorganic acids as a stripping agent or detergent.

Claims

1. A method for the separation of lutetium and ytterbium by solvent extraction, characterized in that, The method comprises the steps of: Step 1: dissolving a sample to be separated containing a lutetium compound and a ytterbium compound, and a carboxylic complexing agent in water as an aqueous phase; Step 2: dissolving an organic phosphorus extractant in a diluent as an organic phase; mixing the organic phase and the aqueous phase to perform extraction, and obtaining an organic phase containing lutetium and ytterbium; Step 3: adding the carboxylic complexing agent to the organic phase obtained in Step 2 to perform stripping, and realizing separation of lutetium and ytterbium; The carboxylic complexing agent comprises one or more of ethylenediaminetetraacetic acid, acetic acid, lactic acid, diethylenetriaminepentaacetic acid, 1,3-diamino-2-propanol-N,N,N',N'-tetraacetic acid, and bis(2-aminoethyl) ether N,N,N',N'-tetraacetic acid; The organic phosphorus extractant comprises one or more of tributyl phosphate, trioctylphosphine oxide, di(2-ethylhexyl)phosphoric acid, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester, bis(2,4,4-trimethylpentyl) phosphinic acid, di(2-ethylhexyl) phosphinic acid, and dimethylheptyl methylphosphonate.

2. The method of claim 1, wherein the method is a method of enhanced extraction separation of lutetium from ytterbium. The diluent comprises one of kerosene, heptane, and dodecane.

3. The method of claim 1, wherein the method is a method of enhanced extraction separation of lutetium from ytterbium. The lutetium compound comprises one or more of a nitrate, a chloride, and a sulfate of lutetium; and the ytterbium compound comprises one or more of a nitrate, a chloride, and a sulfate of ytterbium.

4. The method of claim 1, wherein the method is a method of enhanced extraction separation of lutetium from ytterbium. The extraction temperature in Step 2 is room temperature, and the extraction time is more than 10 minutes.

5. The method of claim 1, wherein the method is a method of enhanced extraction separation of lutetium from ytterbium. The molar concentration of the organic phosphorus extractant in the organic phase in Step 2 is 3-30 mmol / L.

6. The method of claim 1, wherein the method is a method of enhanced extraction separation of lutetium from ytterbium. The molar concentration of the carboxylic complexing agent in the aqueous phase in Step 1 is 1-50 mmol / L.

7. The method of claim 1, wherein the method is carried out by using a mixture of 0.1 M HNO3 and 0.1 M HCl as the eluent. The pH of the aqueous phase in Step 1 is 1-3; and the volume ratio of the organic phase to the aqueous phase in Step 2 is 1:10-10:

1.

8. The method of claim 1, wherein the method is a method of enhanced extraction separation of lutetium from ytterbium. The molar concentration of the carboxylic complexing agent in the organic phase in Step 3 is 1-50 mmol / L.

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