Purification method of high-lanthanum feed liquid

Abstract

The invention discloses a purification method of high-lanthanum feed liquid, and particularly relates to the field of separation and purification. Comprising the following steps: filling phosphonic acid functionalized silicon-based extraction resin into a double-layer separation column with a circulating water bath, enabling feed liquid under a certain condition to flow into the separation column under the action of a pump, preferentially adsorbing trace cerium, praseodymium and neodymium rare earth impurity ions in the feed liquid, and enabling lanthanum to flow out along with the feed liquid, thereby realizing efficient separation of lanthanum and impurity elements. After the effluent is tested by an inductively coupled plasma emission spectrometer (ICP-OES), a single lanthanum solution is obtained, and the removal rate of rare earth impurity ions cerium, praseodymium and neodymium is up to 97%. The method is characterized in that after feed liquid containing trace impurities is introduced into a column, the impurities in the feed liquid can be efficiently removed after the feed liquid passes through the column once, and a pure lanthanum solution can be obtained without a traditional adsorption-desorption process. By adopting the technical scheme, the problems that the existing method for obtaining the high-purity lanthanum solution is complicated in process and relatively high in cost are solved, and the method has the advantages of simplicity and high efficiency.

Description

Technical Field

[0001] The present invention relates to the field of separation and purification, and in particular to a method for purifying a high-lanthanum liquid. Background Art

[0002] Due to their unique electronic structure, rare earth elements (REEs) play an irreplaceable role in functional materials such as magnetism, optics, and electricity. As a core supplier of rare earths, my country accounts for 70% of global production and 90% of separation capacity. However, current rare earth separation technology still faces bottlenecks in achieving high purification and ultra-low impurity control. In the large-scale production of lanthanum (La), the thorough removal of associated impurity ions such as cerium (Ce), praseodymium (Pr), and neodymium (Nd) has become a key issue restricting its high-end applications.

[0003] Lanthanum is one of the most abundant rare earth elements and is widely used in cutting-edge fields such as high-transmittance optical glass, laser crystals, and integrated circuit films. However, even trace amounts of cerium, praseodymium, and neodymium impurities (such as 10 -5 ~10 -4 The presence of impurities (e.g., cerium, cerium, and cerium-ionized impurities) can also reduce the transmittance of optical materials, lower the luminous efficiency of fluorescent materials, or worsen the insulation properties of electronic devices. For example, in the gate oxide layer of very large-scale integrated circuits, cerium impurities can introduce lattice defects, significantly affecting device stability. In laser crystals, praseodymium and neodymium impurities can form competing performance levels, interfering with the laser output wavelength.

[0004] At present, the solvent extraction method is mainly used in industry to achieve the crude separation of lanthanum and other rare earth elements. However, this method has a low separation efficiency for elements of the same group such as cerium, praseodymium, and neodymium. Especially when the lanthanum concentration in the feed solution is high, the relative content of impurity ions is difficult to reduce to the target level. Although the ion exchange method can selectively adsorb lanthanum through resin, its selectivity is poor and it is easy to cause cross-contamination. Although membrane separation technology is theoretically feasible, the selectivity and stability of membrane materials for complex systems with high lanthanum feed solutions still need to be broken through. In addition, the traditional multi-stage separation method leads to problems such as a decrease in lanthanum recovery rate (usually less than 85%) and a large consumption of acid and alkali, which further aggravates the cost and environmental pressure of high-purity lanthanum preparation.

[0005] Scholars generally divide lanthanide rare earths into three components: light, medium and heavy. Among them, lanthanum, cerium, praseodymium and neodymium are classified as light rare earths. Due to the existence of the lanthanide contraction effect, the separation of rare earth elements in the same component is extremely difficult. It is worth noting that the chemical properties of cerium, praseodymium and neodymium are highly similar to those of lanthanum, and they often exist as paragenetic minerals in ores. The difficulty of separating them is far greater than removing radioactive impurities such as uranium and thorium. As the purity requirements for lanthanum in semiconductors, optoelectronics and other fields have jumped from 5N (99.999%) to 5N5-6N (99.9995%-99.9999%), existing technologies can no longer meet the needs of ultra-trace control of impurity ions. Therefore, the development of an efficient, low-cost and highly selective deep impurity removal method is of great significance to improving the international competitiveness of high-purity lanthanum products and ensuring the high-end development of my country's rare earth industry chain. Summary of the Invention

[0006] The present invention aims to provide a method for purifying a high-purity lanthanum solution, which solves the problem that the existing method for obtaining ultra-high-purity lanthanum solution is complicated and has poor stability.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows: a method for purifying a high-lanthanum liquid comprises the following steps:

[0008] S1. Dissolve a compound containing lanthanum, cerium, praseodymium, and neodymium in an appropriate amount of ultrapure water at room temperature, wherein the concentration of lanthanum is controlled to be 1 g / L-10 g / L, the ratio of the lanthanum ion concentration to the sum of the cerium, praseodymium, and neodymium ion concentrations is 100:1-0.1, and the acidity is adjusted to pH ≥ 3 to prepare a feed solution;

[0009] S2, fully dissolving the acidic phosphine extractant in a sufficient amount of dichloromethane, and uniformly mixing it with the silica-based carrier in a certain proportion in a flask, then heating it in a water bath, vacuuming the flask to gradually reduce the internal pressure of the flask to below 500 hPa, and drying it in a vacuum drying oven to obtain a phosphonic acid functionalized silica-based extraction resin;

[0010] S3, soaking the extraction resin in the prepared ultrapure water, absorbing the resin that sinks to the bottom and injecting it into the inner layer of the separation column, and after the separation column is filled with resin, performing acid balancing treatment on the separation column so that the acidity in the separation column is the same as the acidity of the feed solution;

[0011] S4. The separation column of step S3 is placed vertically, and the temperature of the outer circulating water bath is set to >25°C. The feed liquid is allowed to flow into the separation column from either end and out from the other end. The effluent is collected and the concentrations of cerium, praseodymium, and neodymium in the effluent are detected. When the concentration of any one of cerium, praseodymium, and neodymium is greater than or equal to 5% of the concentration of cerium, praseodymium, and neodymium in the feed liquid, the addition of the feed liquid is stopped. The collected solution is the purified lanthanum solution, and the concentrations of lanthanum, cerium, praseodymium, and neodymium in the solution are detected using ICP-OES.

[0012] S5. Use nitric acid or sulfuric acid solution as a desorption solution to desorb the cerium, praseodymium, and neodymium elements adsorbed in step S4, collect the effluent and detect the concentration of cerium, praseodymium, and neodymium. When the concentration of any one of cerium, praseodymium, and neodymium is less than 10% of the corresponding element concentration of cerium, praseodymium, and neodymium in the feed solution, stop adding the desorption solution, adjust the acidity in the separation column, and regenerate the resin in the separation column for reuse.

[0013] Furthermore, in step S1, ultrapure water is used to adjust the acidity of the solution.

[0014] Through the above settings, the solution is adjusted to the optimal acidity to enhance the adsorption capacity.

[0015] Furthermore, the lanthanum compound is lanthanum nitrate.

[0016] Furthermore, the acidic phosphine extractant is a mixture of C272 and P507 in a volume ratio of 20%-80%.

[0017] Through the above settings, different synergistic extraction ratios can enhance the separation effect.

[0018] Furthermore, in step S2, the carrier comprises any one of a porous silicon-based polymer and a macroporous adsorption resin D101.

[0019] Through the above settings, this type of resin has the advantages of high mechanical strength, high temperature resistance, and radiation resistance, which is beneficial to column separation experiments.

[0020] Furthermore, the ratio of the extractant to the carrier is 1:1-5.

[0021] Through the above arrangement, different ratios of extractant to carrier can expand the processing capacity of the resin.

[0022] Furthermore, in step S4, the separation column has a length of 30-50 cm, and a diameter:column length ratio of 1:30-60.

[0023] By using the above setup, the resin processing capacity can be increased by utilizing the optimal column dimensions.

[0024] Compared with the existing technology, this solution has the following beneficial effects:

[0025] 1. The present invention designs an acidic phosphine-based silicon-based extraction resin that exhibits weak adsorption for lanthanum but strong adsorption for impurity elements such as cerium (Ce), praseodymium (Pr), and neodymium (Nd). Through a temperature-field-enhanced column process, the impurity elements in the feed liquid are adsorbed to obtain a purified solution, without the need for a desorption stage to obtain a purified lanthanum feed liquid. Since the impurity elements are present in small quantities compared to lanthanum, the efficiency of the resin is greatly improved. A high-purity lanthanum feed solution can be obtained through a single chromatographic column, greatly simplifying the purification process and improving production efficiency.

[0026] 2. In the lanthanum ion effluent obtained by the present invention, the removal rate of Ce, Pr, and Nd impurity ions is greater than 97%, and the product quality is excellent.

[0027] 3. The present invention uses strong acid to desorb all ions, achieving a near 100% recovery rate for all ions after desorption, significantly improving resource utilization. Furthermore, the resin can be regenerated and reused to produce a high-purity lanthanum solution, saving costs while improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a preparation flow chart of a method for purifying a high-lanthanum feed solution according to Example 1;

[0029] Figure 2 is a flow chart of the resin synthesis in Example 1;

[0030] Figure 3 This is a schematic diagram of an element separation column experiment in a method for purifying a high-lanthanum liquid in Example 1. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below through specific embodiments:

[0032] Example 1

[0033] like Figures 1 to 3 As shown, a method for purifying a high-lanthanum liquid comprises the following steps:

[0034] S1. Preparation of high lanthanum feed solution: Use an appropriate amount of ultrapure water to dissolve lanthanum nitrate, cerium nitrate, praseodymium nitrate, and neodymium nitrate with a purity greater than 99%. Then add ultrapure water and control the concentration of lanthanum to 1 g / L, and the concentration of cerium, praseodymium, and neodymium to 0.01 g / L. Then use ultrapure water to adjust the acidity of the solution to pH 4 to prepare the feed solution.

[0035] S2. Preparation of a Phosphonic Acid-Functionalized Silica-Based Extraction Resin: The preparation principle involves vacuum impregnation of two acidic phosphine extractants into a porous silica-based polymer support (SiO2-P). Hydrogen bonding within the support anchors the extractants within the pores of the silica spheres, resulting in a phosphonic acid-functionalized silica-based extraction resin. The specific method is as follows: P507 (mono-2-ethylhexylphosphonate) and C272 (bis(2,4,4-trimethylpentyl)phosphonic acid) extractants are thoroughly mixed at a specific molar ratio (P507:C272 = 1:1) and dissolved in a sufficient amount of dichloromethane to obtain an organic solution. In this scheme, the synergistic extraction of P507 and C272 enhances separation efficiency. The organic solution and the porous silica-based polymer support (SiO2-P) are then transferred to an eggplant-shaped flask at a specific mass ratio (extractant:support mass ratio of 1:2) and placed on a rotary evaporator for uniform mixing. The use of porous silicon-based polymers in this scheme can increase the carrier's mechanical strength, heat resistance, cost-effectiveness, and corrosion resistance. The eggplant-shaped flask is then placed in a water bath at 35°C. The pressure is reduced to 500 hPa at a rate of 30 hPa / 30 min, and the pressure is maintained for sufficient time to allow the complete evaporation of the dichloromethane. Once only solids are observed within the flask, the product is removed and dried in a vacuum oven at 40°C for 24 hours. The resulting product is a phosphonic acid-functionalized silicon-based extraction resin.

[0036] S3. Preparation for separation: The purification device of this embodiment includes a peristaltic pump, a chromatographic column (i.e., a separation column), a thermostatic control device, a liquid collecting vessel, and a compression hose. The connection method and function of each component are as follows: The peristaltic pump delivers the feed liquid from one end of the separation column to the inner column filled with resin through the compression hose. The outer layer of the column uses a thermostatic control device to pass circulating water of a certain temperature to maintain a constant temperature. The feed liquid flows through the inner column and flows out from the other end and is collected by the liquid collecting vessel. The column length of the chromatographic column is 30 cm, and the diameter: column length = 1:60. It adopts a wet filling method, that is, the resin is soaked in ultrapure water, and the resin that sinks to the bottom is sucked up by a rubber-tipped dropper and filled into the separation column. After filling, the separation column is acid-balanced with 2 bed volumes of nitric acid solution so that the acidity in the chromatographic column is consistent with the acidity of the feed liquid, wherein the pH of the nitric acid solution is 4.

[0037] S4. Single-column separation operation: Under normal pressure and a water bath temperature of 25°C, use a peristaltic pump to add the feed liquid from the top of the separation column at a flow rate of 2.0 bed volumes / hour and let it flow out from the bottom of the separation column. Manually collect the effluent at a flow rate of 1.2 bed volumes / part, and test the concentrations of the impurity elements Ce, Pr, and Nd in the effluent. When the concentration of any of these elements reaches or exceeds 10% of the concentration of Ce, Pr, or Nd in the feed liquid, stop adding the feed liquid. The collected solution is the lanthanum purification solution, and the concentrations of La, Ce, Pr, and Nd therein are analyzed.

[0038] At the same time, the lanthanum-containing solution remaining in the pipeline was flushed with 2 bed volumes of nitric acid solution at a flow rate of 2.0 bed volumes / hour, wherein the pH of the nitric acid solution was 4. The resulting solution was collected and returned to the feed solution of step S1 for subsequent purification.

[0039] S5. Desorption and Regeneration: Desorb the impurity elements adsorbed in step S4 using a 1M HNO3 solution (HNO3 solution is used as the desorbent) at a flow rate of 2.0 bed volumes / hour. The effluent is manually collected at a flow rate of 1.5 bed volumes / part, and the concentrations of the impurity elements Ce, Pr, and Nd are measured. When the concentration of any of these elements is less than 10% of the corresponding concentration of Ce, Pr, or Nd in the feed solution, the addition of the desorbent solution is stopped, and the pipeline is flushed with pure water at a constant flow rate (1.0 volume / hour) until the pH reaches ≥3.

[0040] In this solution, the extractant adsorbs impurity rare earth ions through the combined effects of ion exchange and coordination. The hydrated ions of different rare earth ions are somewhat different, so the adsorption effects of different hydrated ion radii are different. Experiments have shown that the extractant has the worst adsorption capacity for lanthanum ions among rare earth elements, but has better adsorption effects on cerium, praseodymium, and neodymium. Therefore, after being prepared into a resin and operated using a purification device, it can effectively remove other rare earth elements in lanthanum, thereby achieving the purpose of purifying the lanthanum solution. Experiments have shown that the extractant has the worst adsorption capacity for lanthanum ions among rare earth elements. Therefore, after being prepared into a resin and operated using a column separation device, it can effectively remove other rare earth elements in lanthanum, thereby achieving the purpose of purifying lanthanum.

[0041] Example 2

[0042] A method for purifying a high-lanthanum liquid comprises the following steps:

[0043] S1. Preparation of high lanthanum feed solution: Use an appropriate amount of ultrapure water to dissolve lanthanum nitrate, cerium nitrate, praseodymium nitrate, and neodymium nitrate with a purity greater than 99%. Then add ultrapure water and control the concentration of lanthanum to 5 g / L, and the concentration of cerium, praseodymium, and neodymium to 0.01 g / L. Then use ultrapure water to adjust the acidity of the solution to pH 4 to prepare the feed solution.

[0044] S2. Preparation of a Phosphonic Acid-Functionalized Silica-Based Extraction Resin: The preparation principle involves vacuum impregnation of two acidic phosphine extractants into a porous silica-based polymer support (SiO2-P). Hydrogen bonding within the support anchors the extractants within the pores of the silica spheres, resulting in a phosphonic acid-functionalized silica-based extraction resin. The specific method is as follows: P507 (mono-2-ethylhexylphosphonate) and C272 (bis(2,4,4-trimethylpentyl)phosphonic acid) extractants are thoroughly mixed at a specific molar ratio (P507:C272 = 2:1) and dissolved in a sufficient amount of dichloromethane to obtain an organic solution. In this scheme, the synergistic extraction of P507 and C272 enhances separation efficiency. The organic solution and the porous silica-based polymer support (SiO2-P) are then transferred to an eggplant-shaped flask at a specific mass ratio (extractant:support mass ratio of 1:1) and placed on a rotary evaporator for uniform mixing. The use of porous silicon-based polymers in this scheme can increase the carrier's mechanical strength, heat resistance, cost-effectiveness, and corrosion resistance. The eggplant-shaped flask is then placed in a water bath at 35°C. The pressure is reduced to 500 hPa at a rate of 30 hPa / 30 min, and the pressure is maintained for sufficient time to allow the complete evaporation of the dichloromethane. Once only solids are observed within the flask, the product is removed and dried in a vacuum oven at 40°C for 24 hours. The resulting product is a phosphonic acid-functionalized silicon-based extraction resin.

[0045] S3. Preparation for separation: The purification device of this embodiment includes a peristaltic pump, a chromatographic column (i.e., a separation column), a thermostatic control device, a liquid collecting vessel, and a compression hose. The connection method and function of each component are as follows: The peristaltic pump delivers the feed liquid from one end of the separation column to the inner column filled with resin through the compression hose. The outer layer of the column uses a thermostatic control device to pass circulating water of a certain temperature to maintain a constant temperature. The feed liquid flows through the inner column and flows out from the other end and is collected by the liquid collecting vessel. The column length of the chromatographic column is 30 cm, and the diameter: column length = 1:30. It adopts a wet filling method, that is, the resin is soaked in ultrapure water, and the resin that sinks to the bottom is sucked up by a rubber-tipped dropper and filled into the separation column. After filling, the separation column is acid-balanced with 2 bed volumes of nitric acid solution so that the acidity in the chromatographic column is consistent with the acidity of the feed liquid, wherein the pH of the nitric acid solution is 4.

[0046] S4. Single-column separation operation: Under normal pressure and a water bath temperature of 35°C, use a peristaltic pump to add the feed solution from the top of the chromatographic column at a flow rate of 2.0 bed volumes / hour and allow it to flow out from the bottom of the column. Manually collect the effluent at a flow rate of 1.2 bed volumes / part, and test the concentrations of the impurity elements Ce, Pr, and Nd in the effluent. When the concentration of any of these elements reaches or exceeds 10% of the concentration of Ce, Pr, or Nd in the feed solution, stop adding the feed solution. The collected solution is the lanthanum purification solution, and the concentrations of La, Ce, Pr, and Nd therein are analyzed.

[0047] At the same time, the lanthanum-containing solution remaining in the pipeline was flushed with 2 bed volumes of nitric acid solution at a flow rate of 2.0 bed volumes / hour, wherein the pH of the nitric acid solution was 4. The resulting solution was collected and returned to the feed solution of step S1 for subsequent purification.

[0048] S5. Desorption and Regeneration: Desorb the impurity elements adsorbed in step S4 using a 1M HNO3 solution (HNO3 solution is used as the desorbent) at a flow rate of 2.0 bed volumes / hour. The effluent is manually collected at a flow rate of 1.5 bed volumes / part, and the concentrations of the impurity elements Ce, Pr, and Nd are measured. When the concentration of any of these elements is less than 10% of the corresponding concentration of Ce, Pr, or Nd in the feed solution, the addition of the desorbent solution is stopped, and the pipeline is flushed with pure water at a constant flow rate (1.0 volume / hour) until the pH reaches ≥3.

[0049] Example 3

[0050] A method for purifying a high-lanthanum liquid comprises the following steps:

[0051] S1. Preparation of high lanthanum feed solution: Use an appropriate amount of ultrapure water to dissolve lanthanum nitrate, cerium nitrate, praseodymium nitrate, and neodymium nitrate to a purity greater than 99%. Then add ultrapure water and control the concentration of lanthanum to 10 g / L, and the concentration of cerium, praseodymium, and neodymium to 0.01 g / L. Then use ultrapure water to adjust the acidity of the solution to pH 4 to prepare the feed solution.

[0052] S2. Preparation of a Phosphonic Acid-Functionalized Silica-Based Extraction Resin: The preparation principle involves vacuum impregnation of two acidic phosphine extractants into a porous silica-based polymer support (SiO2-P). Hydrogen bonding within the support anchors the extractants within the pores of the silica spheres, resulting in a phosphonic acid-functionalized silica-based extraction resin. The specific method is as follows: P507 (mono-2-ethylhexylphosphonate) and C272 (bis(2,4,4-trimethylpentyl)phosphonic acid) extractants are thoroughly mixed at a specific molar ratio (P507:C272 = 4:1) and dissolved in a sufficient amount of dichloromethane to obtain an organic solution. In this scheme, the synergistic extraction of P507 and C272 enhances separation efficiency. The organic solution and the porous silica-based polymer support (SiO2-P) are then transferred to an eggplant-shaped flask at a specific mass ratio (extractant:support mass ratio of 1:5) and placed on a rotary evaporator for uniform mixing. The use of porous silicon-based polymers in this scheme can increase the carrier's mechanical strength, heat resistance, cost-effectiveness, and corrosion resistance. The eggplant-shaped flask is then placed in a water bath at 35°C. The pressure is reduced to 500 hPa at a rate of 30 hPa / 30 min, and the pressure is maintained for sufficient time to allow the complete evaporation of the dichloromethane. Once only solids are observed within the flask, the product is removed and dried in a vacuum oven at 40°C for 24 hours. The resulting product is a phosphonic acid-functionalized silicon-based extraction resin.

[0053] S3. Preparation for separation: The purification device of this embodiment includes a peristaltic pump, a chromatographic column (i.e., a separation column), a thermostatic control device, a liquid collecting vessel, and a compression hose. The connection method and function of each component are as follows: The peristaltic pump delivers the feed liquid from one end of the separation column to the inner column filled with resin through the compression hose. The outer layer of the column uses a thermostatic control device to pass circulating water of a certain temperature to maintain a constant temperature. The feed liquid flows through the inner column and flows out from the other end and is collected by the liquid collecting vessel. The column length of the chromatographic column is 50 cm, and the diameter: column length = 1:50. It adopts a wet filling method, that is, the resin is soaked in ultrapure water, and the resin that sinks to the bottom is sucked up by a rubber-tipped dropper and filled into the separation column. After filling, the separation column is acid-balanced with 2 bed volumes of nitric acid solution so that the acidity in the chromatographic column is consistent with the acidity of the feed liquid, wherein the pH of the nitric acid solution is 4.

[0054] S4. Single-column separation operation: Under normal pressure and a water bath temperature of 45°C, use a peristaltic pump to add the feed solution from the top of the chromatographic column at a flow rate of 2.0 bed volumes / hour and allow it to flow out from the bottom of the column. Manually collect the effluent at a flow rate of 1.2 bed volumes / part, and test the concentrations of the impurity elements Ce, Pr, and Nd in the effluent. When the concentration of any of these elements reaches or exceeds 10% of the concentration of Ce, Pr, or Nd in the feed solution, stop adding the feed solution. The collected solution is the lanthanum purification solution, and the concentrations of La, Ce, Pr, and Nd therein are analyzed.

[0055] At the same time, the lanthanum-containing solution remaining in the pipeline was flushed with 2 bed volumes of nitric acid solution at a flow rate of 2.0 bed volumes / hour, wherein the pH of the nitric acid solution was 4. The resulting solution was collected and returned to the feed solution of step S1 for subsequent purification.

[0056] S5. Desorption and Regeneration: Desorb the impurity elements adsorbed in step S4 using a 1M HNO3 solution (HNO3 solution is used as the desorbent) at a flow rate of 2.0 bed volumes / hour. The effluent is manually collected at a flow rate of 1.5 bed volumes / part, and the concentrations of the impurity elements Ce, Pr, and Nd are measured. When the concentration of any of these elements is less than 10% of the corresponding concentration of Ce, Pr, or Nd in the feed solution, the addition of the desorbent solution is stopped, and the pipeline is flushed with pure water at a constant flow rate (1.0 volume / hour) until the pH reaches ≥3.

[0057] The following is the ICP-OES test report of Example 1

[0058] Table 1 Feed liquid composition analysis report (mg / L)

[0059] element La Ce Pr Nd concentration 1001.8 12.095 8.763 9.354

[0060] Table 2 Effluent composition analysis report (mg / L)

[0061]

[0062] The above are only embodiments of the present invention, and common knowledge such as the specific structure and / or characteristics of the scheme are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for purifying a high-lanthanum liquid, characterized in that: The steps include: S1. Dissolve a compound containing lanthanum, cerium, praseodymium, and neodymium in an appropriate amount of ultrapure water at room temperature, wherein the concentration of lanthanum is controlled to be 1 g / L-10 g / L, the ratio of the lanthanum ion concentration to the sum of the cerium, praseodymium, and neodymium ion concentrations is 100:1-0.1, and the acidity is adjusted to pH ≥ 3 to prepare a feed solution; S2, fully dissolving the acidic phosphine extractant in a sufficient amount of dichloromethane, and uniformly mixing it with the silica-based carrier in a certain proportion in a flask, then heating it in a water bath, vacuuming the flask to gradually reduce the internal pressure of the flask to below 500 hPa, and drying it in a vacuum drying oven to obtain a phosphonic acid functionalized silica-based extraction resin; S3, soaking the extraction resin in the prepared ultrapure water, absorbing the resin that sinks to the bottom and injecting it into the inner layer of the separation column, and after the separation column is filled with resin, performing acid balancing treatment on the separation column so that the acidity in the separation column is the same as the acidity of the feed solution; S4. The separation column of step S3 is placed vertically, and the temperature of the outer circulating water bath is set to >25°C. The feed liquid is allowed to flow into the separation column from either end and out from the other end. The effluent is collected and the concentrations of cerium, praseodymium, and neodymium in the effluent are detected. When the concentration of any one of cerium, praseodymium, and neodymium is greater than or equal to 5% of the concentration of cerium, praseodymium, and neodymium in the feed liquid, the addition of the feed liquid is stopped. The collected solution is the purified lanthanum solution, and the concentrations of lanthanum, cerium, praseodymium, and neodymium in the solution are detected using ICP-OES. S5. Use nitric acid or sulfuric acid solution as a desorption solution to desorb the cerium, praseodymium, and neodymium elements adsorbed in step S4, collect the effluent and detect the concentration of cerium, praseodymium, and neodymium. When the concentration of any one of cerium, praseodymium, and neodymium is less than 10% of the corresponding element concentration of cerium, praseodymium, and neodymium in the feed solution, stop adding the desorption solution, adjust the acidity in the separation column, and regenerate the resin in the separation column for reuse.

2. A method for purifying a high-lanthanum feed liquid according to claim 1, wherein: In step S1, ultrapure water is used to adjust the acidity of the solution.

3. A method for purifying a high-lanthanum feed solution according to claim 1, wherein: The lanthanum compound is lanthanum nitrate.

4. A method for purifying a high-lanthanum feed solution according to claim 1, wherein: The acidic phosphine extractant is a mixture of C272 and P507 with a volume ratio of 20%-80%.

5. A method for purifying a high-lanthanum feed solution according to claim 1, wherein: In step S2, the carrier comprises any one of a porous silicon-based polymer and a macroporous adsorption resin D101.

6. A method for purifying a high-lanthanum feed solution according to claim 1, characterized in that: The ratio of the extractant to the carrier is 1:1-5.

7. A method for purifying a high-lanthanum feed solution according to claim 1, characterized in that: In step S4, the separation column has a length of 30-50 cm, and a diameter:column length ratio of 1:30-60.

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