Method for intensively extracting and separating lutetium and ytterbium

Abstract

The invention relates to the technical field of rare earth element separation and extraction, and discloses a method for reinforced extraction and separation of lutetium and ytterbium, which comprises the following steps: step 1, dissolving a to-be-separated sample containing a lutetium compound and an ytterbium compound and a carboxylic acid complexing agent in water as a water phase; 2, dissolving an organic phosphorus extraction agent in a diluent to serve as an organic phase; the organic phase and the water phase are mixed for extraction, and an organic phase containing the lutetium element and the ytterbium element is obtained; and step 3, adding a carboxylic acid complexing agent into the organic phase obtained by extraction in the step 2 to carry out back extraction so as to realize separation of lutetium and ytterbium. According to the method, the organophosphate extraction agent serves as a positive-sequence ligand, the carboxylic acid complexing agent serves as a reverse-sequence ligand, separation of lutetium and ytterbium is enhanced through the synergistic effect of the positive-sequence ligand and the reverse-sequence ligand, the separation factor of lutetium and ytterbium is effectively increased, the separation and purification process of lutetium and ytterbium is effectively shortened, and the separation efficiency and equipment investment are improved.

Description

Technical Field

[0001] The invention relates to the technical field of separation and extraction of rare earth elements, and in particular to a method for enhanced extraction and separation of lutetium and ytterbium. Background Art

[0002] Rare earth elements are a group of metal elements with similar physical and chemical properties, including 15 lanthanide elements from lanthanum (La) to lutetium (Lu) and two elements, scandium (Sc) and yttrium (Y). Among them, ytterbium (Yb) and lutetium are located at the last two digits of the lanthanide elements and belong to heavy rare earth elements. Ytterbium can form +2 and +3 oxidation states, but the +3 oxidation state is more stable, while lutetium only forms the +3 oxidation state. Ytterbium and lutetium have excellent magnetism, fluorescence and catalysis, which makes them have important applications in modern industrial and scientific fields such as electronic products, new energy, aerospace, catalysts and medical treatment.

[0003] Ytterbium is mainly used as shielding coating material and magnetostrictive material. It can also be used to manufacture lasers, high-strength alloys, optical fiber amplifiers, etc. Some of its compounds can be used as catalysts in organic synthesis and homogeneous catalytic reactions; Lutetium can be used as a catalyst in petrochemical industry, raw material for magnetic bubble storage, raw material for special alloys, etc. Its isotopes 177 Lu has the ability to integrate diagnosis and treatment and unique radiochemical properties, and plays an important role in the field of nuclear medicine. Since ytterbium and lutetium belong to the same lanthanide series and are located adjacent to each other, their trivalent ion radii are 85.8pm and 84.8pm respectively, and their chemical properties are very similar, which brings great challenges to separation and purification.

[0004] Common rare earth separation methods include fractional crystallization, fractional precipitation, oxidation-reduction, solvent extraction, ion exchange, etc. Among them, solvent extraction has the advantages of good separation effect, large production capacity, strong process controllability, and easy large-scale continuous production. It has become the most widely used and most mature method in the separation of rare earth elements. At present, the research and development of extractants used for heavy rare earth separation is mainly focused on phosphorus (phosphine) extractants with low pKa values ​​and high steric hindrance. Because of their excellent extraction and separation performance between heavy rare earth elements, they are highly favored in industrial applications.

[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)phosphinic acid (Cyanex 272) are widely used in heavy rare earth separation, but there are still many problems in the application of Lu / Yb separation, such as the low separation factor of P204 for Lu / Yb and the difficulty of stripping; although P507 has a higher separation factor for Lu / Yb (SF=1.6-1.8), it has the defects of high stripping acidity and incomplete stripping; the stripping acidity of Cyanex272 is reduced, but the separation factor for Lu / Yb is still not high enough, only 1.31, and when extracting rare earth elements, the viscosity of the organic phase increases, resulting in a decrease in extraction efficiency. Some new extractants such as di(2-ethylhexyl)phosphinic acid (P227) and di-(2,3-dimethylbutyl)phosphonic acid (HYY-2) have slightly higher separation factors than Cyanex272, but P227 has slow extraction kinetics and is difficult to synthesize. HYY-2 has a shorter carbon chain, which results in a higher solubility in aqueous phase.

[0006] Chinese patent document CN100352954A reported a process for separating rare earth elements by adding an extracting system with a modifier, using P507 + methyl heptanol to improve the selectivity and stripping ability of some rare earth elements, but the separation factor of Lu / Yb was not improved;

[0007] In another patent disclosure (CN102618736A), a method for extracting rare earth elements using trialkylmethylammonium 2-ethylhexylphosphonate ([A336][P507]) and trialkylmethylammonium di(2-ethylhexyl)phosphonate ([A336][P204]) was reported. During the extraction process of this process, cations and anions have synergistic and competitive effects, which improves the separation efficiency of rare earth elements. At the same time, it has the advantages of low acidity required for extraction and stripping and low acid consumption. However, the separation factor of Lu / Yb in this system is limited. The separation factor of Lu / Yb in a mixed rare earth solution of [A336][P204] is only 1.85. Summary of the invention

[0008] The present invention aims at solving 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, and provides a method for enhanced extraction and separation of lutetium and ytterbium. The method uses an organic phosphate extractant as a positive sequence ligand and a carboxylic acid complexing agent as a reverse sequence ligand, and strengthens the separation of lutetium and ytterbium through the synergistic effect of the positive and reverse sequence ligands, thereby effectively improving the lutetium and ytterbium separation factor.

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

[0010] A method for enhanced extraction and separation of lutetium and ytterbium comprises the steps of:

[0011] Step 1, dissolving a sample to be separated containing a lutetium compound and an ytterbium compound and a carboxylic acid complexing agent in water as an aqueous phase;

[0012] Step 2, dissolving an organophosphorus extractant in a diluent as an organic phase; mixing the organic phase and the aqueous phase for extraction to obtain an organic phase containing lutetium and ytterbium elements;

[0013] Step 3, adding a carboxylic acid complexing agent to the organic phase obtained by extraction in step 2 for back extraction to achieve separation of lutetium and ytterbium.

[0014] The carboxylic acid complexing agent includes 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, bis(2-aminoethyl) ether N,N,N',N'-tetraacetic acid (OBETA), and the like.

[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 preferably used as the complexing agent.

[0016] The organophosphorus extractant includes one or more of tributyl phosphate (TBP), trioctylphosphine oxide (TOPO), di(2-ethylhexyl) phosphoric acid (P204), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (P507), bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272), di(2-ethylhexyl)phosphinic 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 more than 10 minutes. The preferred extraction time is 10-30 minutes. The separation effect is not very ideal when the extraction time is less than 10 minutes, and the extraction balance is basically maintained after 30 minutes.

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

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

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

[0023] During the stripping in step 3, the molar concentration of the carboxylic acid complex 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 the present invention, an organic phosphate extractant is used as a positive-sequence ligand, and a carboxylic acid complexing agent is used as a reverse-sequence ligand. The synergistic effect of the positive-sequence ligands is used to enhance the separation of lutetium and ytterbium, effectively improve the lutetium and ytterbium separation factor, effectively shorten the separation and purification process of lutetium and ytterbium, and improve the separation efficiency and equipment investment.

[0026] (2) The reverse ligand carboxylic acid complexing agent of the present invention can be used as a detergent and a stripping agent at the same time, which reduces the acid and alkali consumption in the separation process of lutetium and ytterbium, and has the advantages of economy, environmental protection and high efficiency; BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the effect of P350 concentration on Lu / Yb separation effect in Example 1.

[0028] Figure 2 This is the effect of C272 concentration on Lu / Yb separation effect in Example 2.

[0029] Figure 3 This is the effect of P227 concentration on Lu / Yb separation effect in Example 3.

[0030] Figure 4 This is the effect of DTPA concentration on Lu / Yb separation effect in Example 4.

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

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

[0033] Figure 7 The figure shows the effect of the stripping agent DTPA concentration on the Lu / Yb stripping effect in Example 7. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiment. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Those skilled in the art can make modifications or equivalent substitutions based on the understanding of the technical scheme of the present invention without departing from the spirit and scope of the technical scheme of the present invention, and all should be included in the protection scope of the present invention.

[0035] The raw materials used in the following specific embodiments are all purchased from the market. Extraction distribution ratio D, separation factor SF of lutetium and ytterbium Lu / Yb , the calculation formulas for extraction rate E and stripping rate S are as follows:

[0036]

[0037] Among them, [M] aq,ini is the initial concentration of rare earth ions in the aqueous phase before extraction, [M] aq,eq is the equilibrium concentration of rare earth ions in the aqueous phase after extraction, [M] s is the equilibrium concentration of rare earth ions in the aqueous phase after stripping, D Lu Refers to the extraction distribution ratio of lutetium, D Yb Refers to the extraction distribution ratio of ytterbium.

[0038] Example 1

[0039] Using P350 as the extractant, the effect of P350 concentration on the extraction separation was investigated. At the same time, the Lu / Yb separation effect was compared when a certain amount of DTPA was added 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 mixture containing Lu 3+ and Yb 3+ DTPA carboxylic acid extractant was added to some samples to make the concentration of DTPA carboxylic acid extractant 10 mmol / L, while no DTPA was added to some samples. The pH of the solution was adjusted to 2 with nitric acid to obtain an aqueous phase to be extracted.

[0041] Step 2, dissolving the extractant P350 organophosphorus extractant in the diluent dodecane to make its concentration 3mmol / L, 4.5mmol / L, 6mmol / L, 7.5mmol / L, 9mmol / L, 18mmol / L, 27mmol / L, 30mmol / L, respectively, to obtain an organic phase.

[0042] Step 3: The organic phase and the aqueous phase were mixed in equal proportions, placed in an oscillator at room temperature and oscillated at 300 rpm for 30 minutes, and then centrifuged at 3000 rpm for 2 minutes for phase separation. Lu in the aqueous phase before and after extraction was measured using ICP-OES. 3+ and Yb 3+ concentration, and calculate the distribution ratio (D), separation factor (SF) by the following formulas (1)(2)(3) Lu / Yb ) and extraction efficiency (E).

[0043] The results are as follows Figure 1 As shown in Figure 2, with the increase of P350 concentration, the extraction rate of Lu and Yb increased significantly. 3+ and Yb 3+ The extraction capacity is strong. When the amount of P350 increases from 3mmol / L to 7.5mmol / L, the extraction rates of Lu and Yb increase from 48.3% and 34.1% to 94.9% and 91.1%, respectively. When 9mmol / L of P350 is used, almost all extraction of Yb and Lu can be achieved. In this process, the change of P350 concentration has no obvious effect on the separation factor of Lu / Yb. Lu / Yb Stable at 1.80~1.82.

[0044] When DTPA was added to the aqueous phase, P350 3+ and Yb 3+ The extraction efficiency of Lu 3 + and Yb 3+ The extraction rates of P350 and DTPA were only 48.7% and 27.7%, respectively, which was mainly attributed to the competition between the complexation of Lu and Yb by the reverse ligand DTPA and the extractant. Since P350 preferentially extracted Lu, while DTPA preferentially complexed Yb, the two formed a "push-pull" synergistic extraction effect, which effectively improved the separation effect of Lu / Yb. As shown in Table 1, SF Lu / Yb It increased from about 1.81 to about 2.52, which is much higher than most of the reported extraction systems.

[0045] Table 1 Separation factor of Lu / Yb when P350 is used as 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] The extraction experiment was carried out according to the method of Example 1, using C272 as the extractant to explore the effect of its concentration on the extraction separation, and the extraction results after adding 1 mM DTPA were compared.

[0049] like Figure 2 As shown in the figure, with the increase of C272 concentration, the extraction rate of Lu and Yb increased significantly. Among them, when DTPA was not added, the extraction rate changed significantly with the C272 concentration. When the C272 concentration was 30mmol / L, the extraction rates of Lu and Yb reached more than 80%. In this process, the change of C272 concentration had no significant effect on the separation factor of Lu / Yb. Lu / Yb When DTPA was added to the aqueous phase, the extraction rates of Lu and Yb decreased significantly and increased linearly with the concentration of C272. Similar to the results of Example 1, the introduction of DTPA also increased the separation factor of Lu / Yb. As shown in Table 2, SF Lu / Yb Increased to around 2.23.

[0050] Table 2 Separation factors of Lu / Yb when C272 is used as extractant and 1mM DTPA is used as 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] The extraction experiment was carried out according to the method of Example 1, using P227 as the extractant, and the effect of its concentration on the extraction separation was explored. At the same time, the extraction results after adding 1 mM DTPA were compared.

[0054] like Figure 3 As shown in the figure, with the increase of P227 concentration, the extraction rate of Lu and Yb increased significantly. Among them, when DTPA was not added, the extraction rate changed significantly with the P227 concentration. When the P227 concentration was 30mmol / L, the extraction rates of Lu and Yb reached more than 97%. In this process, the change of P227 concentration had no obvious effect on the separation factor of Lu / Yb. With the increase of its concentration, the SF Lu / Yb When DTPA was added to the aqueous phase, the extraction rates of Lu and Yb decreased significantly and increased linearly with the concentration of P227. Similar to the results of Examples 1 and 2, the introduction of DTPA increased the separation factor of Lu / Yb. As shown in Table 3, SF Lu / Yb Increased to around 2.40.

[0055] Table 3 Separation factors of Lu / Yb when P227 is used as extractant and 1mM DTPA is used as 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 are all enhanced extraction and separation systems formed by an organophosphorus extractant and a carboxylic acid complexing agent DTPA. Since the organophosphorus extractants themselves have different extraction and separation abilities for Lu and Yb, the final extraction systems formed are also different. By comparing the extraction rate and separation factor, it can be obtained that: P350>P227>C272.

[0058] Example 4

[0059] The effect of the concentration of the carboxylic acid complexing agent DTPA on the extraction and separation of Lu / Yb was studied. According to the method of Example 1, the concentration of the 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 the same.

[0060] like Figure 4 As shown, the extraction system has a great influence on Lu 3+ / Yb 3+ The extraction rate of Lu / Yb is negatively correlated with the concentration of DTPA. In addition, the separation coefficient of Lu / Yb increases with the increase of DTPA concentration. As shown in Table 4, when the DTPA concentration increases from 0 to 1 mmol / L, the SF Lu / Yb From 1.81 to 2.58; when the DTPA concentration reached 1-10 mmol / L, SF Lu / Yb Basically stable and unchanged.

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

[0062]

[0063]

[0064] Example 5

[0065] The extraction time was based on the method in Example 1, wherein the concentration of the 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 the Lu 3+ / Yb 3+ The influence of extraction efficiency.

[0066] like Figure 5 As shown in Table 5, when the oscillation time is less than 10 min, the system has a 3+ / Yb 3+ The extraction rate and separation factor of 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 rate and separation factor 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 the initial pH of the aqueous phase on the Lu / Yb extraction and separation effect was studied. The extraction experiment was carried out according to the method in Example 1, wherein the concentration of the extractant P350 in the organic phase was 9 mmol / L, the concentration of DTPA in the aqueous phase was 1 mmol / L, and 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 As shown in Table 6, when pH = 1, SF Lu / Yb =1.75, at this time DTPA is 3+ / Yb 3+ The complexation of DTPA to Lu was almost completely inhibited, and the separation of Lu / Yb was achieved only by the extraction of P350. 3+ / Yb 3+ The complexation of SF is too strong, the extraction rate is significantly reduced, and Lu / Yb separation cannot be achieved; when pH = 2, SF Lu / Yb At this time, the extraction effect of P350 and the complexation effect of DTPA achieved the synergistic enhancement of the separation of Lu / Yb.

[0072] Table 6 Extraction rate and separation factor of Lu / Yb at different initial pH of aqueous phase

[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] DTPA was used as a stripping agent to remove Lu from the organic phase obtained under pH = 2 in Example 6. 3+ / Yb 3+ A stripping experiment was conducted. A DTPA solution with a concentration of 1-10 mmol / L was prepared, and its pH was adjusted to 2 with nitric acid. The loaded organic phase and the DTPA solution were mixed in equal proportions, and a stripping experiment was conducted according to the method in Example 1.

[0076] Table 7 Stripping rate and separation factor of Lu / Yb at different stripping agent 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 As shown in Table 7, when stripping with DTPA, Lu 3+ and Yb3+ The stripping rate of Lu 3+ and Yb 3+ The stripping rate of SF was the highest, which was 71% and 48% respectively. However, the Yb / Lu separation effect was maintained at a high level during the stripping process. When the DTPA concentration was ≥4mmol / L, SF Yb / Lu ≥2.59. This shows that DTPA can replace inorganic acid as a stripping agent or detergent.

Claims

1. A method for enhanced extraction and separation of lutetium and ytterbium, characterized in that: Includes steps: Step 1, dissolving a sample to be separated containing a lutetium compound and an ytterbium compound and a carboxylic acid complexing agent in water as an aqueous phase; Step 2, dissolving an organophosphorus extractant in a diluent as an organic phase; mixing the organic phase and the aqueous phase for extraction to obtain an organic phase containing lutetium and ytterbium elements; Step 3, adding a carboxylic acid complexing agent to the organic phase obtained by extraction in step 2 for back extraction to achieve separation of lutetium and ytterbium.

2. The method for enhanced extraction and separation of lutetium and ytterbium according to claim 1, characterized in that: The carboxylic acid complexing agent includes 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.

3. The method for enhanced extraction and separation of lutetium and ytterbium according to claim 1, characterized in that: The organophosphorus extractant includes one or more of tributyl phosphate, trioctyl phosphine 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.

4. The method for enhanced extraction and separation of lutetium and ytterbium according to claim 1, characterized in that: The diluent includes one of kerosene, heptane and dodecane.

5. The method for enhanced extraction and separation of lutetium and ytterbium according to claim 1, characterized in that: 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.

6. The method for enhanced extraction and separation of lutetium and ytterbium according to claim 1, characterized in that: In step 2, the extraction temperature is at room temperature and the extraction time is more than 10 minutes.

7. The method for enhanced extraction and separation of lutetium and ytterbium according to claim 1, characterized in that: The molar concentration of the organophosphorus extractant in the organic phase of step 2 is 3-30 mmol / L.

8. The method for enhanced extraction and separation of lutetium and ytterbium according to claim 1, characterized in that: The molar concentration of the carboxylic acid complexing agent in the aqueous phase of step 1 is 1-50 mmol / L.

9. The method for enhanced extraction and separation of lutetium and ytterbium according to claim 1, characterized in that: The pH of the aqueous phase in step 1 is 1-3; the volume ratio of the organic phase to the aqueous phase in step 2 is 1:10-10:

1.

10. The method for enhanced extraction and separation of lutetium and ytterbium according to claim 1, characterized in that: During the stripping in step 3, the molar concentration of the carboxylic acid complex in the organic phase is 1-50 mmol / L.

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